I have one from NW (the newer black/red ones) I use for travel. My mother has given me a couple of others from UA that I'm keeping in case the NW one falls apart... and also in case I have any afore-mentioned short-stay overnight visitors. As a grad student, I almost never fly int'l biz/FC so I hang on to the few I have.

Were my situation otherwise, I'd probably donate them to charity or to a nursing home (excellent suggestion ^).