My group consists of:

Prot Pally
Resto Druid
Shadow Priest
Fire Mage
Affliction Lock

Frost/Unholy DK
Resto Shaman
Fury Warrior
Beast Mastery Hunter
Combat Rogue

I've been trying archavon for about two weeks now, but he keeps stomping me. My best attempt got him down to 500k. I'm noticing a couple of things that I really need to fix, but I'm still trying to figure out how to deal with the random nature of the fight.