DPS: BLM. I do have SMN as 60 also, and they share gear (minus weapon), but BLM is my bread and butter. Making things explode with Fire 4 and/or Flare never gets old.
Tank: Leveled them all together, more or less, and after much gnashing of teeth over which one to go forward with gearing wise, I've opted for DRK. I like the overall toolkit a bit more. Having a placeable aoe as well as a gap closer that's off gcd? Yes, please. WAR would be my choice if left between it and PLD. Funny enough, though, I can safely say I enjoy all of the tanks and their nuances.
Healer: Honestly haven't played healer much in this game in terms of actual relevant group content. SCH was dragged to 60 by leveling SMN, while WHM and AST are at 52 currently. Oddly enough, I find WHM the most satisfying due to smacking people with big ass rocks a la SWTOR Jedi Sages and for having the mother of all aoe stuns with Holy.