Specs for leveling untwinked or with minimal twinking/power leveling. Focuses on respecing as little as possible, killing as fast and safe as possible while minimizing downtime.
Druid
1-34:
Talent Calculator - World of Warcraft
Ferocity is an obvious choice, Feral Instinct lets you Prowl around and tank instances (the threat is also useful for escort quests). Brutal Impact is an absolute must (put points in it at 15 and 16), it lets you get Regrowths off at early levels and later on it lets you Pounce > Shred/Mangle > Shred. Feral Swiftness at 20-21 followed by Sharpened Claws and Primal Fury. Then it's Feary Fire (feral), Savage Fury and Shredding Attacks.
35-50:
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The difference is if you plan on tanking instances while leveling up. If so, max out Survival of the fittest ASAP, otherwise Heart of the Wild > LotP + Imp. LotP, Predatory Instincts and then Mangle at 50.
51-70:
Talent Calculator - World of Warcraft with 4 points left over
Pick up Furor, Natural Shapeshifter, *2* points in Naturalist, OoC, max out Naturalist and take Nurturing Instinct.
From 60-70, pick up the 2 following trinkets from quests
Ancient Crystal Talisman - Items - World of Warcraft or
Glowing Crystal Insignia - Items - World of Warcraft (depends on faction) *AND*
Oshu'gun Relic - Items - World of Warcraft. Use those over normal DPS trinket. Whenever you shift out to heal, simply pop the trinkets to get a huge increase in healing done and reduced downtime.
Hunter
Hunter is very simple: for 1-70
Talent Calculator - World of Warcraft
Endurance Training > Imp. Revive Pet > Focused Fire > 1 in Thick Hide > Beastial Swiftness > Unleashed Fury > Intimidation > Imp. Mend Pet > Bestial Discipline > Frenzy > Bestial Wrath > Animal Handler > 2 Ferocious Inspiration > Serpent's Swiftness > TBW. Rest in Marks.
The amount of life healed by Spirit Bond is pathetic. Putting 2 more points in DPS talent for your pet is pretty much going to save you more downtime than 2 points in that talent.
Mage
There's 2 ways to go with a Mage, either AoE Frost or Frostbolt spam.
AoE:
Talent Calculator - World of Warcraft
Frostbolt:
Talent Calculator - World of Warcraft
It's personal preference. AoE is riskier but it's really easy to gather up a 3-4 mobs before lvl 40 and AoE them down, even while questing. Frostbolt is safer but you won't be able to AoE nearly as well compared to the AoE build. For both builds, do the following: Elemental Precision > 2 in Imp. Frostbolt > Permafrost (this is a MUST) > 3 more in Imp. Frostbolt > Icy Veins. Even with the AoE build, you still want a decent Frostbolt utility.
Please note that Ice Shards is completely useless early on. With under 5% crit without Shatter and with the talent costing a whole 5 points to max out, it makes it terrible and a very small DPS increase until higher levels.
40-58 AoE:
Talent Calculator - World of Warcraft for Outlands, go Frostbolt since AoEing in Outlands isn't practical
Frostbolt 40-50ish:
Talent Calculator - World of Warcraft
Max out Winter's Chill and Emp. Frostbolt, pick up Water Elemental at 50 and then fill up Frost talents as you see fit (Imp Blizzard, Frostbite, Artic Winds are all good).
At 70:
Talent Calculator - World of Warcraft
After you're done with Frost talents, pick up the Arcane stuff (Arcane Subtlety is nice for instancing when you have a terrible tank, just use Arcane Blast/Missiles) to finish up.
Paladin
3 choices this time. All Paladins should go Ret spec until Outlands unless they're absolutely want to instance pre-BC. Ret is worthless for instances compared to almost every other spec out there.
1-70 Ret:
Talent Calculator - World of Warcraft
At 20, pick up SoC and then 3 points in Pursuit of Justice. Vindication > Conviction > 2h Spec > Vengeance > Sanctified Seals > Repentance > 1 in Sanctified Judgement > Crusader Strike. After that you have 2 options, Holy for Spiritual Focus to heal yourself or Prot for 3% hit for more DPS. Hit is easy to get in Outlands so I suggest Holy and then putting the rest of the points in Ret.
58-70 Prot:
Talent Calculator - World of Warcraft
You start putting points in Ret at 59 only. This is for leveling as Prot in Outlands (which is effective). You'll want to instance a lot to take advantage of being Prot, but Prot Paladins are amazing for tanking the Outland instances (except the last boss of Sethekk) and there's always a high demand for good tanks. Just pick up all the tank oriented quest rewards and all the spell dmg plate/mail/leather (in that order) to solo. Keep a 1h + shield and smack stuff up with lots of spell dmg and SoR/Consecrate.
58-70 Holy:
Talent Calculator - World of Warcraft
Put all the points in Holy first and then go to Prot. Stack up as much spell damage as possible as SoR/Consecrate stuff down. Keep a 1h + Shield on and pick up healing gear/spell damage gear. Congratulations, you're a healer and all you have to do to find a group for Outland instances is ask in General/LFG once!
Priest
Only 1 spec, really. The only "thing" is if you can't afford to stack as much Spirit as possible before level 40, then it might be a good idea to pick up Wand Spec at lvl 10 instead of starting with Spirit Tap.
1-40:
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Take Imp. Shadow Word: Pain before Shadow Focus, Mind Flay at 20. Put points in Shadow Reach and Darkness as "fillers" for Shadow Form.
40+:
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Get Vampiric Touch and go into Discipline. After that, just put the points where you want (Shadow Affinity, Imp. Mind Blast and Shadow Power are all good choices - crit sucks for shadow Priests though). If you plan on instancing, get Shadow Affinity before Imp. Mind Blast at lvl 23-24.
If you plan on on healing:
Talent Calculator - World of Warcraft
Lightwell is *AMAZING* if you actually use it and bitch at your group members to use it. While in instances, try to Mind Blast/SW
mobs to get Spirit Tap to proc. For leveling, stack as much Spirit as possible.
Rogue
1-70:
Talent Calculator - World of Warcraft
The utility Imp. Gouge gives greatly surpasses the extra dodge. From 15-19, max out Precision, then Deflection > Riposte. After that it's 4 points in DW spec, Blade Flurry, 4 points in Weapon Spec**, Weapon Expertise, Max out DW and Weapon Spec + 1 in Aggression and then AR at 40. After that go Assassination. Imp Poisons over Vile Poisons because you'll want to use utility Poisons while instancing (Mind Numbing/Crip/Wounding) and the higher proc chance while leveling is nice, especially without Shiv.
For Weapon spec: pre-BC, Maces are harder to come by than Swords, but the stun is very, very nice. Swords are nice and you get a lot of quest reward swords if you choose that route. In Outlands, there's only 1 good MH mace before 70, so respec to either Sword or Fist (if you aren't Sword already, that is).
NOTE: If you can get your hands on it, the Fang set expertise bonus is a keeper until early to mid 40s. More dps and less Dodges/Parries on your Gouge can't be beaten by meager gear upgrades for a long time.
Shaman
Two ways for Shamans. You can choose to start with
Talent Calculator - World of Warcraft and then go Enhance or start Enhance right away. Whatever you do, respec out of it at 40 and go pure Enhance.
1-70:
Talent Calculator - World of Warcraft
Use Imp. Lightning Shield as a filler to go higher in the tree (you can use Anticipation, too). At 35: Mental Quickness > 2 in Weapon Mastery > SS > DW > DW spec > Unleashed Rage > Shamanistic Rage. After that go Resto to pick up Healing Focus and Nature's Guidance. Put the rest of your points in Weapon Mastery.
1-70 elemental:
Talent Calculator - World of Warcraft
Elemental itemization is very lacking pre-BC so I suggest to stick to Enhance until Outlands at least. Max out Elemental first and then put the rest in Restoration.
Warlock
No matter what anyone says, Felguard spec will increase your downtime. While you're Funneling/Bandaging your Felguard, the Affliction Warlock is already dotting more mobs and looting what he killed.
1-39:
Talent Calculator - World of Warcraft
Demonology first, 3 points in Imp. Voidwalker at 15-17; Imp. Health Funnel at 18-19 and Fel Domination at 20. After that it's Imp. Corruption > Imp Drain Soul > Suppression > Fel Concentration > Imp. CoA > Grim Reach. Neither Affliction or Demo can fully support non-stop Fear/Dotting before lvl 40. This build lets you use a Voidwalker to tank mobs while you get your DoTs applied on them (2 non-resisted Torments and the mob will die before it reaches you, usually). Just send in the Voidwalker on a mob, apply all dots. Dot another mob and fear it, send the Voidwalker to a third mob, dot that one and clean up. Rince and repeat. Mend/loot while the Voidwalker is casting Consume Shadows.
40-63:
Talent Calculator - World of Warcraft
Fill up Affliction. Pick up Dark Pact at 40 and then max Contagion > Imp Howl of Terror > Imp. Life Tap > UA. Then put the points in Demonology to get Demonic Aegis (you'll have 2 points in it once you get Fel Armor at 62). Max it out at 63 then go put the rest in Affliction (Imp. CoA, Nightfall, Shadow Embrace). The idea is to sacrifice *EVERYTHING* for spell dmg to be able to kill mobs with Immolate + Corr + CoA + SL + UA. With enough +shadow dmg, it's even possible to kill mobs without having to Immolate. Life Tap when you're going to be at full health and Dark Pact when you aren't full health.
Warrior
There's a thread about pure DPS output of 3 fully twinked out and power leveled Warriors on the WoW forums that says Fury wins out for leveling speed. Unless you're planning on getting power leveled and enchanting every epic weapon you buy with Crusader, the spec I'm listing here will win out over Fury builds (plus it lets you TANK instances easily in Outlands, provided you have the gear).
1-63:
Talent Calculator - World of Warcraft
Imp Thunderclap at 15, Imp. Overpower at 20-21. 2h Spec, Anger Management and Imp. Disciplines as fillers to get MS at 40. After MS fill up the lower tiers to get Endless Rage and then go Fury. Note that you can pick up Cruelty at lvl10 and respec for MS at 40. Works fine either way. If the mob dies quickly, don't bother with Demo/Tclap, otherwise try to put them up when you charge in to greatly reduce damage taken.
63-70:
Talent Calculator - World of Warcraft
This will let you tank instances fairly easily in Outlands. If you go that route, make sure to pick up
Regal Protectorate - Items - World of Warcraft it'll save you more potions and deaths than you can imagine. After 63, just put points into Cruelty and Imp. Revenge. Max out the one you want the most. Your fighting sequence will be: Charge > MS > Tclap + Demo if the mob won't die quickly > Defensive Stance and spam Revenge + MS. Extra Rage, if any, should be spent on Heroic Strike or Sunder.