Last summer, when I was playing a bard (though I never did get her past about 12 or 13), the argument was between STR and DEX. There have been quite a few changes made since then, though, and I've no idea what Bards primarily use. I'm not sure how much I'd put into WIS, since in theory lots of the songs can be balanced out with proper rests and I don't know how many direct mana-using spells they get. As for VIT, I've been wondering myself if that might not be an overlooked stat in the long term.
I guess we'll have to see as we go along, or hope someone with a higher level bard late in beta will stop by and enlighten us.
