Banana's are the best. But not when they are unripe. Just a little hint of green is best, as badger said, but I've seen them completely green and they don't look to tasty. Banana's seem to digest quickly though, and if you do like Joe Gardner and mash them up into pudding, then there are no stringy things to mess with, you don't have to peel them, and they are a poor man's power gel(not quite as thick).
Rich, I feel your pain dude