I have 3x70 Spriests, mostly S2 gear. BGs are fun but you cant rock them like a Shammy team can. Arenas you will lose to any team with rogue/rogues.

Rogues are the worst part of being a spriest atm, they resist everything you do including fears and will waste your guys even if theyre in crap gear. Most other classes you can do a MB & SWD combo to instagib unless you get a resist or they have unsually high HP. Hopefully dispersion and imp shadowform/fade will help in WotLK but atm dont bother.