Go heavy Disc. and other damage mitigation talents.
Something along these lines. I put this build together pretty quick but here are just a few things I thought of.
http://www.wowhead.com/?talent=dxMGzIGtrzVofEzho
1. Maxing out damage reduction in Disc & Holy because you are the first to be targeted (unless the opponents are full of CC).
2. ImpMana Burn. A big duh for anyone who arenas regularly, this is one thing that really separates priests from the other healers. Its great for burning other healers OOM. Really works well against any caster though, I won a match yesterday where my DPS partner went down and I won a 1v1 v. frost mage by mana burning him and then dotting & wanding him to death.
3. Focused Power. Mass dispel is extremely useful at the beginning of a fight because if you aim it right you can dispel every buff the other team has on in one fell swoop. Not to mention Mass Dispel is the only spell in the game that can remove Pally's bubbles. Its a real shock to them when you get them down to 15%, and the bubble up to heal, only to find that their bubble gets dispelled.
4. Spell Warding instead of Divine Fury. You rarely have time to cast any type of Gheal in arena so might as well skip over Divine Fury. You make your money by casting renew, prayer of mending, and flash heal. Instead go with Divine Fury, should really help v. those Pom/Pyro mages.
5. Holy Nova & Holy Reach. Unless you are grouped with a mage (arcane blast), use it to find those annoying stealthing opponents.
Edited, Aug 16th 2007 7:51:27pm by MookusOU