I'm at around 4650 right now. All computer system counts are cartridges only, but do include utility/language cartridges. These are almost all domestic, less than 20 are imports.
Playstation: 892 unique, 942 total (5 imports)
NES: 566
Gameboy/Color: 531 (2 imports)
Genesis: 297
Atari 2600: 296
N64: 281 plus 6 demos
SNES: 247 (3 imports)
Dreamcast: 227 unique, 249 total (2 imports)
Playstation 2: 213 unique, 215 total
TI 99-4/A: 91
Intellivision: 89
Game Gear: 87 (2 imports)
Saturn: 82
SMS: 78
Xbox: 71
Gamecube: 63
Gameboy Advance: 49
Atari XE: 48
Sega CD: 48
Atari 7800: 34
Tandy CoCo: 33
C64/128: 31
Odyssey 2: 31
Atari 5200: 31
Neo Geo Pocket Color: 30 (2 imports)
Sega 32X: 26
Lynx: 25
Colecovision: 21
game.com: 19
VIC-20: 17
Tubografx 16: 14
3DO: 7
Virtual Boy: 9 (1 import)
Astrocade: 9
Jaguar: 8
Arcadia 2001: 5 (but no system)
Vectrex: 1
Aquarius: 1
Sad thing is, the larger this gets, the less time I have to play anything!