Hey, so I need some advice.

2 of my friends have been playing 2s to gear up there new toons and are now "good" geared!
(almost fully Grev)

And they asked me if i could play 3s with them.

They play:

Holy Paladin + Affli (could spec destro) lock.

What would be the best class/spec to compliment these 2?
I was thinking i could play my unholy death knight maybe..

P.s as of last night I now have all classes at 90! (got my priest to 90 last night wohoo)



Some insight to a good comp using those 2 classes and how the "normal tact" ( just serg or outlast? )