2 Paladins 3 Mages

[Apatheist]

Can you explain in a little more detail why pally priest i have also been planning pally pally same as dreadone. same as him i thought running the cross buffs on pallys and having wisdom on mages would be better?

Two paladins don't really do much for mages. All you need is salvation. Kings is a minimal DPS increase of perhaps 1-2% crit if you have enough intellect on your gear. Wisdom is negligible past level 20-30 since your pulls will last ~30 seconds and you'll drink after every pull with a paladin tank anyway. Wisdom is 39ish mana per 5 when talented, which means on an average trash pull of around 30 seconds you'll gain ~230 mana from wisdom. That's not even one arcane explosion. Wisdom is great in longer fights (raids) but it doesn't do a lot for you in short fights. Especially when you have free water from mages to drink between every pull.

One paladin gives you either kings/sanctuary on your tank, wisdom on your healer and salvation on your DPS. That's all you need. Likewise, I always use retribution aura on my tank. Devotion aura isn't bad but it's nowhere near as strong as priests inspiration which is straight 25% armor increase on your tank for 15 seconds every time a heal crits. Inspiration is huge.

Priest is just a stronger dungeon healer overall. You get a HoT, shield, party-wide heals, shackle, fear and an offensive dispel to remove annoying buffs like the fire aura on Scarlet Wizards.

If you plan on PvPing a lot I'd choose paladin because they're much tankier when you get jumped by rogues or warriors. In PvE priest is the superior choice by a fair margin IF you already have one paladin in your party for salvation.