I did Onyxia and some Zul Gurub with two friends, a level 75 Druid and a level 72 Death Knight. We had the druid tanking and Death Knight on DPS. It went fine, I even healed with my Balance spec. I didn't really need to heal so I mostly nuked.
Got my mind on my money achievement
Onyxia quest turn in
Awesome to finally win this one and see what all the fuss was about!