Seriously though, I've got 9 bikes, only about 7 of which actually function. I don't think too poorly of it though, because it means my friends and I can go riding when they visit instead of having to drive around, and most of them are junkyard rescues, meaning that if I didn't fix them up, they'd be scrap metal, and that would just be sad.
I don't mind getting rid of bikes now and again, since I've got a few that are my favorites, and the others are just extras, or ones I picked up because I thought a friend might want them. I like Chimblysweep's plan of "If you don't ride it for a year, sell it." Sounds reasonable.
Just put up more hooks in the ceiling, and hang up a few more bikes, you can fit a lot of bike in not a lot of space with front wheel hooks.
peace,
sam