I would say, try to split things up so that you're playing the least amount of roles possible. (roles being tank, healer, dps)

Why? You can be MUCH more effective at what you do if you minimize the amount of multi-tasking. I'd go with Ualaa's suggestion of 3x dps for one, and tank/healer for the other.


HOWEVER: If you're looking for a challenge, do exactly the opposite. Get as many different classes with as many different roles as you possibly can. Why? Because it's fun to challenge yourself.