Warrior + Shaman + Hunter + Hunter + Hunter
would be enjoyable and easy

Paladin + Priest + Lock + Lock + Lock
not as strong or easy as the first team, but you could ignore a lot more mechanics with self healing and no facing issues. I would maybe take a Rdruid healer instead.

Death Knight + Druid + Shaman + Shaman + Shaman
Very odd tank healer combo, considered the worst together, but in my experience on my Rdruid solo i've felt like my hots smooth out the spikiness of the Blood dk's healthbar. Triple Ele is amazing though and would carry, but more so with a pally tank.

Druid + Paladin + Mage + Mage + Mage
Solid team, but i think priest goes better with a bear, and holy nova works well with AE. Need really strong tank aggro in this group, Blood dk's have good aoe aggro and damage, but if i went blood dk i'd keep the pally healer.

Paladin + Priest + Priest + Priest + Priest
if i did this i'd go spriestx4. It's the last expansion you can do this sadly, but it's also not that strong anymore and mana struggles.

Don't like boomies? They are 1 minute cooldown gods atm with starfall.
Tank + RSham + 3x Boomy
easily one of the top comps