1) A 3-speed with a rack and baskets, for going around town and picking up stuff.
2) A dutch-style cargo bike, with plenty of low gears and a trailer hitch for hauling larger amounts of cargo.
3) A nice old road bike, for when I'm in a hurry or just want a fast ride.
4) Some sort of homebuilt recumbent, just because I like building things
5) A folding bike so I can get on the bus or train if necessary.