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!