Boxer briefs, as well. Briefs are way too tight (Do you like choking your mandhood?!), boxers are way too lose (Where am I, a nudist beach?), but boxer briefs find a perfect midway point.

Edit: Apparently Boxer Briefs are everyone's friend.
As a point of appeal, though, I think I'd have to say full boxers. Honestly, I like leaving more to the imagination than just "How hairy is it...?"