2 tanks, one with a DPS offspec, 3 healers, 1 with a DPS offspec, 5 mainspec DPS. Naturally you want buffs that will complement each other. Addons, you want a decent boss mod like DBM or DXE, skada if you want to easily see dps/heals/damage taken, etc. GTFO is great for people who need to get out of things that hurt them. All else is up to personal preference.