I generally prefer an upbeat attitude in my heroes instead of the broody, mopey, tragic guys.
I'm currently playing Bravely Default, and I like how the four heroes complement each other: gentle, steadfast Tiz; spiritual, determined Agnes; frank, resolute Edea; and libidinous yet shrewd Ringabel.
In my own game, the MC, Duran, is friendly bookworm. His allies come to include a brash-but-sweet tomboy, an animalistically honest wildman, a lady knight whose seen many campaigns, a charitable thief, a naively courageous priestess, an undercover cop and a mischievously wise witch.