Scholar, always. I like the other healers but always come back to scholar in the end.
My secondary is dragoon because...I don't know. I just love it more than any other dps class.
My tank is dark knight for whatever reason. It's just the one I have at lvl60. I have warrior and paladin at lvl50 and before Heavensward, my favorite tank was paladin because the warrior's stacks felt weird, which is weird in itself since I've been playing scholar for so long. And yet, I have no trouble managing mp on DRK and keeping darkside up 100% of the time.