I am fundamentally one who strives to provide the most excellent support, therefore my mainly prefer roles are (in descending order, best to worst, although better at some of the jobs down below than those ranked higher up)
Healers, with AST as my main preferred one due to supportive ability with cards.
Ranged, with MCH barely winning due to the lovely burst & tactical play with turrets. It used to completely buy me over, but with the reduced cast on songs in 3.3, whenever I do ranged I go for MCH 45% of the time and BRD 35%. BLM 15% and SMN (due to the continued allocations of stats as I play SCH even more) 5%.
Tanks, with DRK as my go-to for the leveling roulette, mainly for eternal MP & PLD as my trial job. WAR can be deleted for all I care, mainly because I always have TP problems, but that might take a lot more of practice to find out when to stop aoeing and start doing the cheap single target rotation.
Melee dps, interestingly with MNK as a clear winner and NIN at 2nd place due to ongoing damage vs supportive abilities. Aesthetics wise, DRG wins, but because of long animation queue time, thus making me another loldrg, I highly prefer to not go as.