Definitely have to play what is most fun for you, and not let yourself be limited with old archetypes from other games. In beta I watched rogues and clerics effectively tank (some even have a taunt!!). Mages and bards heal... This game is just unlike any others that i've played. It's awesome.
I played a Bard as a main and every warfront I was either top heals or 2nd, and usually the most killing blows to go with it! I absolutely LOVE that class! I will have a chloro alt and a cleric alt as well, the cleric having 2 roles - sent/puri/ward and sham/druid/just (might throw some cabal/inq in there too). In the end I thoroughly enjoyed all 3 of these toons, and will continue with them. I am an alt person through and through, and will likely also have a warrior, but the first 3 will cinch up all the crafting classes for me.
Just a few hours left...WOOT!