I collect game systems, so let's see how many I can remember off the top of my head:
Atari: 2600, 5200, 7800, and Jaguar
Sega: SMS, Genesis, CD, Saturn, Dreamcast, Nomad, Gamegear
Nintendo: NES, SNES, N64, Gamecube, Wii, Gameboy, Gameboy Color, Gameboy Advance, GB Advance SP, Virtual Boy, DS Lite
Playstation: PS, PS2, PS3, PSP
Microsoft: Xbox, Xbox 360
Orphens: Colecovision, Intellivision, Odessey 2, Microvision, Vetrex, TI 994a, Turbographx
I think that's all of them. I have multiples and varients, everybody has at least one game, they all work, and they all get played from time to time.
Edit because I forgot the 3DO