I just love the hardware and all the diferent ways they work. All the differnet controllers, especially during the Gen 1 and 2 consoles. The only games I have for them either came with the purchase, or friends and family have bought them for me from carboots etc. Mega Drive is the only console I've actively gone out and bought CIB games for.
I have some pong machines and handhelds too, but these are the main ones.
Odyssey
Atari 2600 and 5200
Coleco Vision
Intellivision and Voice module unit
Vectrex
NES
Famicon
SNES
N64
Gamecube
Wii
Master System
Mega Drive I and II, 32x and CD
Jaguar
Saturn
Dreamcast
TurboGrafx
Neo Geo
CDI
3DO
Playstation 1, 2 and 3
Xbox and 360
Commodore64, if you count it.
and the most recent purchase, my Fairchild Channel F