Druid (recommended)

Role: Tank/dps(caster/melee)/heal

This is one of the class i recommend if you prefer to play a bit of each

Strength
1. HoT - Best Heals-over-time in game
2. Battle rez - the only class to be able to rez a group mate IN BATTLE/COMBAT
3. Versatile - cat form dps can switch to bear tank if need arise
4. Arena - Resto Druid <--- overpowered in arena (our guild warlock and druid spent 20 mins to kill 1 & and its 2v1 btw) so if you know how to play it, you're hard to kill
5. Low down time on farming - dps in cat form and when your health is low, shape shift and cast HoT, then shape shift back and continue to dps while your mana regen (cat form uses rage similar bar and not mana)

Weakness
1. Moonkin (caster dps) - gears are hard to get for this spec (T4s and above)
2. Rez - cannot do normal rez to party members even if you're out of combat

I'll add in more if i can think of any
I personally would play this as my main if i start all over again