Black Mages. Reasons:

-The outfits are adorable. Especially the hat.
-Vivi is a Black Mage and he is the greatest Final Fantasy character of all time
-They themselves are adorable
-They start off weak but by end game they are ridiculously useful
-Casting elemental magic is cool beans
-I think they suit my personality. Physically weak, but smart (hush). They fight from a distance. They cast cool spells like Blizzard and water, and I love water and ice
-Which leads me too, if I were an FF character I would be a Black Mage. Preferably a Black Mage archer

I like all mages. I am much more about magic than about physical fighters so mages are always superior to other classes to me. I like White Mages, Time Mages, Blue Mages, Red Mages, all of them. But Black Mage definitely takes the cake for me