Good damage dealers are Wiz, Archer. Squishy? Probably.
Good survivers (to have time to deal lot of damage) are BM, Barb, Seeker.
Of those 3 I think BM hits hardest.
For Sin and Psy some people say that are OP in PvP. They can also do lot of dmg,
and Sin on BP can be self-sufficient in many situations.
Plus, stealth is fun (shadow walk, shadow jump, shadow escape...).

I love my Seeker, I can farm fast, tank or solo lot of bosses, and also help ppl level fast.
I also love my Cleric, good for squads (except 1hit AoE by some bosses, including event ones),
and self heal does great job for many solo tasks. But slow as hell for PV, FC or Warsong.
I still don't kow what will be my next (I love Myst), but I think it will be Sin. Or maybe BM.