A IIc will run almost everything that runs on a II+, but no cards.

A IIe will run almost everything that runs on a II+, and almost all cards.

All three will fit in a small space in a closet, but the monitor is always going to be bulky.

Buy the best deal that suits you now and pick up the other two when you can get a good deal. The IIgs can act as any of the above, but it works far better if you treat it as a separate platform.