Compendium of Mage Talent Builds:
This is entirely opinionated by myself. I play a 70 mage on Shadowmoon (US PVP). I've been playing since release as a mage and I've cleared MC, BWL ZG, AQ, Naxx, SSC, and much more (including the Deadmines). I'm also experienced in pvp arenas and I have previously held top 10 in every bracket.
Useful links:
Mage Macros for 2.X:
WoW Forums -> Mage Macro Guide for 2.X
Dueling Videos by Evertras:
WarcraftMovies.com - World of Warcraft Movies
PVP (Player vs. Player)
**NOTE - Until ice block is trainable there aren't many talent specs outside of the realm of frost.
Frost:
17/0/44
Talent Calculator - World of Warcraft
This is a standard build that primarily focuses on 3v3 and 5v5 arenas. I chose talents based on team support rather than individual killing. Improved Counterspell is the highlight of the build. It works to stop druid heals, silence even if you miss, and block out all magic schools. For 2v2 you may want to build around improved cone of cold, permafrost, and improved arcane missiles. Specializing around these is because in 2v2 arenas you're reliant on using faster/instant cast. Frostbolt, unfortunately, is heavily affected by line of sight in the 2v2 bracket with the abuse of pillars.
0/5/56
Talent Calculator - World of Warcraft
Another standard build. It relies on the use of Molten Armor and Impact rather than Frost Armor. It allows you to get everything out of Frost that you want and it's easily modifiable to your play style. Generally, non improved counterspell specs are for your love of Molten Armor or larger brackets where improved counterspell loses its effectiveness.
Summary: Right now, for arenas, there aren’t many specs that are good outside of the realm of frost. There are elementalist variations of talents, but overall it’s a rather dead spec and only for fun.
PVE (Player vs. Environment)
Fire
12/46/3
Talent Calculator - World of Warcraft
Fire is based on improved scorch, mana efficiency, and steady damage. Unlike Arcane, fire is much more +hit dependent and it is much better for mana. A standard rotation is 5x scorch at the start then repeat 8x Fireball (or 6x 9x) > 1x scorch > 8x Fireball (or 6x 9x). Typically a standard raider will spec fire until he has two pieces of Tirisfal or ridiculous gear based around Arcane.
10/48/3
Talent Calculator - World of Warcraft
It’s the same thing except magic attunement was moved for whatever fits your taste.
Arcane
48/13/0
Talent Calculator - World of Warcraft
This is based on arcane missiles and arcane blast. The limit of your damage is your mana, pyroblast is used for presence of mind arcane power damage. You can remove the points in flame throwing for your specific needs. This spec is great for producing very low threat with arcane subtlety.
40/21/0
Talent Calculator - World of Warcraft
Generally a “fun” spec and it allows more versatility than 48/13. However this is more primary for battleground gib. You can also try 41/20/0, 40/0/21, and 41/0/20.
Summary: Fire and Arcane are both great specs. Fire relies more on hit and is better for mana efficiency. Arcane will give you the biggest boom for your mana, but it will also dissolve your mana quickly.