Shaman builds/Pre-WotLK

This information is outdated, but is logged here for reference of past builds only. All of these builds have been invalidated by the 3.0.2 patch.

Solo PvE
The most common leveling Talent tree is Enhancement. Blue posts on the Blizzard Forums even state that this is the designers' intent. At low levels, it's very mana-efficient and therefore has the least downtime while at the same time dealing high amounts of damage. The only drawback is that it's rather gear-dependent, similar to Warriors and Paladins. Strength, attack power, and critical hit are the crucial stats; and Windfury is the melee Shaman's best friend.
 * Enhancement

This Talent tree can also be chosen for leveling. At lower levels, downtime can be a problem, but this is something that elemental shamans deal with at any level. One must simply remember to carry enough water whenever they are questing; leveling as an elemental shaman then becomes smooth and easy. At higher levels, after Water Shield becomes available, helping but not nullifying elemental shamans' troubles with mana regeneration.
 * Elemental

Since items with healing bonuses also grant spell damage, healer specs are not quite as hopeless in solo PvE as they used to be, but it is still not a recommended choice. Damage output is still about half of what's possible with other builds, and this disadvantage is not made up for by the extreme survivability. Leveling with this type of build is only recommended when grouping frequently, and the group needs a dedicated healer (remember that every shaman can off-heal).
 * Restoration

Group PvE
Restoration used to be the only acceptable shaman build in raids, and is the most common one to this day. Resto shamans are fully capable raid/group healers, with some individual strengths which no other healing class provides. Chain Heal is the most mana efficient and universally usable group heal over all classes.
 * Restoration

As in solo play, this talent tree has high DPS potential if the shaman in question is well-geared. The challenge that enhancement shamans face is that they are, as other melee DPSers, completely gear-dependent. Considering melee damage output it's second only to Rogues, and generally above DPS Warriors. Beyond the DPS, Windfury Totem can increase the damage output of the other melee classes by as much as 5%, together with the AP buff from Unleashed Rage and the other totems, raid leaders are usually happy to invite one enhancement shaman to any raid to boost the melee DPS group. A second one may get a spot in the tank group.
 * Enhancement

Elemental shamans bring to a raid many buffs that greatly help caster groups. Their Totem of Wrath, Wrath of Air Totem, and Mana Spring Totems provide powerful benefits to any casters in their group. They are able to pump out massive numbers on DPS meters, and can often top them, with competition only from equally-geared Warlocks and Rogues. Almost any successful 25-man raid incorporates at least one elemental shaman into a caster group. Elemental shamans may have difficulty getting spots in 5-man groups due to their lack of CC, but if the leader of the group is at all intelligent, he or she will realize that it is well worth it to sacrifice a bit of CC for the huge damage potential of a well-played elemental shaman.
 * Elemental

PvP
As in group PvE, Restoration is the most frequently seen build for PvP shamans. They are very capable healers, while still having the ability to interrupt enemy CC's or heals. Among the healer classes, they are very survivable due to mail armor plus shield. Restoration shamans will often join a PvP team with a Warrior, as their Windfury Totem gives the Warrior a potent DPS boost.
 * Restoration

Elemental generally fares better than enhancement in PvP. This is because as a ranged DPSer, elemental shamans are less susceptible to being kited/slowed/rooted. Burst damage can be very high when specced 40/0/21 for Nature's Swiftness, and (like Resto), they survive a little longer in melee situations than other caster classes. As all shamans do, however, they constantly face challenges with their lack of CC and anti-CC capabilities. It is well recognized that elemental shamans generally perform poorly against Rogues and in 2v2 arena matches.
 * Elemental

The characteristics of this tree (low mana usage and very high damage output) remain the same in PvP. Unfortunately, the days of legendary Windfury proc one-shot kills are all but over (anyone remember "Revenge of the Windfury", starring Creed and his Arcanite Reaper?). Nowadays, the common problem in PvP of all shamans hits melee builds particularly bad - they have no crowd control of their own, and are very susceptible to CC themselves.
 * Enhancement

Elemental
The following elemental builds all use restoration as secondary tree, mainly because the talents match well, and also because elemental gear usually has stats which help healing too (turning the elemental shaman into a capable off-healer). In principle it would be possible to put the remaining points in enhancement, but there are no really good synergies between these trees.

Leveling / 5-Man Instances (PVE)
Elemental is considered by some to be a poor choice as a leveling tree until Elemental Mastery becomes available at level 40. However, the grind to level 40 can be done as an elemental shaman just as easily, if not more easily, than as an enhancement shaman. Casting spells makes elemental shamans less gear dependent than enhancement shamans, and as a result they often have an easier time taking on more difficult mobs. At level 40, this 31/0/0 can get in 3 Lightnings and a Shock before the target even reaches melee range, which usually kills said target. While leveling to 70, this build can evolve into this 41/0/20, which is a good endgame build template for elemental shamans. (Note that this particular talent spec is NOT ideal for level 70 PvP, see below for a more optimal spec)

Raiding (PVE)
Raiding is different from small groups and solo play. Spell hit should be maxed, and threat reduction becomes essential. Therefore these talents should be preferred, leading to builds like 41/0/20. If enough gear with mana regeneration is available, it's possible to move the points from Unrelenting Storm to other talents, and since a certain amount of spell hit is unavoidable in endgame gear (actually shamans frequently complain that their endgame gear sports too much spell hit), the points in Nature's Guidance are frequently moved somewhere else too, finally resulting for example in 41/0/20.

PvP
The elemental tree offers some talents which don't boost DPS but increase PvP survivability. Also, the top elemental talent is less valuable than Nature's Swiftness in PvP. Therefore 40/0/21 is a good PvP build.

Enhancement
The key advantages of this tree are very high DPS combined with good endurance. Enhancement Shamans do maximum damage when dual wielding. The Enhancement tree can usually be complemented either by Restoration (with its 3% increased hit chance and increased survivability); or Elemental, which makes the shocks better and thus yields the highest possible DPS, but at the cost of higher mana usage.

Leveling / 5-Man Instances (PVE)
The Standard Enhancement Build matches Enhancement with Restoration. Taking Elemental instead results in the Reverberation Build. With points in Improved Ghost Wolf (making it instant) along with a point in Elemental Focus, it is perfectly suited for soloing and 5-mans.

Raiding (PVE)
Enhancement Shamans are a major DPS class in raids. Since in a raiding environment drawing aggro usually means death for non-tanks, all survivability talents are not needed, and should be replaced with skills that give hit rating or other buffs. An enhancement/resto raiding build would look something like this 0/45/16.

PvP
Enhancement is somewhat tricky in PvP. Although it has the ability to kill enemies very quickly with extreme burst damage, it lacks crowd control abilities. Enhancement Shamans can still take out any class, but need to know very well what they are doing. Stay up close and personal on casters, and keep your distance from hard melee hitters. Swapping in a shield in fights with warriors, hunters, and rogues can improve the odds dramatically. Since PVP fights are very mobile and resisted Earth Shocks and Frost Shocks can spell defeat, Totemic Mastery and Nature's Guidance are extremely valuable talents for PVP. 0/47/14 is a typical build. Common variants choose Shield Specialization over Ancestral Guidance or move a point from Mental Quickness to Unleashed Rage. This 18/43/0 build uses Elemental instead.

Mixed (PvE & PvP)
0/47/14 is a multi-purpose build that can raid, instance, solo, and be a surviving force in PvP. It grabs nearly all useful Enhancement talents, and spends only the bare minimum of points in Restoration to get the essential Nature's Guidance. It includes controversial talents like Toughness, which now halves movement-slowing time when maxed in addition to increasing armor; Improved Ghost Wolf, which is a PvP and utility thing; and Mental Quickness, which is a solo/hybrid Talent. If needed, points can be removed from these Talents and be put into Anticipation, Improved Weapon Totems, Guardian Totems, and/or Improved Lightning Shield.

Restoration
It's hard to propose a reasonable levelling build, because soloing with a resto shaman is tedious at best. It's usually enough to keep a set of healer gear - similar to shadow priests, shamans can heal well enough for the occasional instance even without the proper talents. Restoration is an endgame healer spec to which shamans should switch when they hit level 70.

That is not to say that leveling with a Restoration spec is impossible. The very good survivability, especially at lvl50+ when you get the Earth Shield talent, makes questing actually very easy. You can simply AOE pull mobs and solo almost any elite, allowing you to complete many quests marked as 'group quests' on your own. Party members in the "occasional instance" will be very pleased if you are specced to healing, and you won't have to drink every other pack. The reduced DPS is quite well compensated by the high survivability that allows AOE and reduces downtime.

Since Ancestral Knowledge is about the only useful talent for a healer outside the resto tree, shamans usually spend a lot more than the mandatory 41 points in resto (0/0/41). Talents like Ancestral Healing together with Tidal Mastery, Nature's Guardian and Improved Reincarnation are highly useful PvE talents, a common PvE build is this 0/5/56. If mana is no issue, points from Totemic Focus can be moved to other talents, similarly those in Focused Mind are not mandatory.

In PvP, the combination of Nature's Guardian with Earth Shield makes a resto shaman very hard to kill. On top of that, they can heal very well, and give the earth shield to others while not under attack themselves. A PvP spec can do away with all the raid-specific talents like Healing Grace, 0/7/54 is an example. Improved Ghost Wolf is a highly useful talent in the outdoor battlegrounds or world PvP.

Actually the difference between raid and PvP resto specs is rather small, depending on playstyle and gear available, shamans can find a dual-purpose spec which is good in both, PvE and PvP.

For a more versatile PVP spec could be something to consider. It offers more protection against various classes due to longer range Earthbind Totem and damage reduction from Elemental Warding.

Other Resto PVP Specs that are good for arena are the following and. They assume that you're using mostly lesser healing waves as your primary method of healing and are using a shield.

Hybrid builds
A plethora of hybrid builds can be found in the forums. Many shamans claim they can tank, dps and heal. A common argument runs along the lines "I can dps while no heals are needed, heal if damage spikes come in, and tank in an emergency". During leveling groupings this brings great flexibility to groups and affords the Shaman to fill in multiple roles as needed. In endgame raids, unfortunately, this line of reasoning is fundamentally flawed. The endgame is all about specialization. The healing argument is always valid, because every shaman can heal in an emergency. The tank argument is true only for emergencies and only if there's a large discrepancy in gear or player skill. The Shaman class is not designed to main tank and the main tank should do his job, not the shaman.

Here is one viable hybrid spec for the leveling and endgame: The elemental/resto build 31/0/30. Taken by itself, this build delivers about 80% of each, the healing capacity of a resto shaman, and the DPS output of an elemental build. Since the DPS output of an elemental shaman is about 90% of that of a "pure" ranged damage dealer, a raid would sacrifice 20% of a healer (plus one earth shied and a mana tide) for about 70% of a ranged damage dealer. The flexibility gained allows to dynamically shift from ranged DPS to healer and back. This can be useful if an instance has different boss types (DPS race and battle for survival), it also speeds up trash clearing.