I don't think I'm even close, but I'll check anyway:
I'm not sure either, so its count off time!
1) Apple II
2) Arcadia 2001
3) Atari 2600
4) Atari 5200
5) Atari 7800
6) Atari Jaguar
7) Atari Lynx
8) Bally Astrocade
9) Colecovision
10) Commodore 64
11) Fairchild Channel F
12) Intellivision
13) Macintosh
14) Nintendo SNES
15) Nintendo Gameboy
16) Nintendo Gameboy Advance
17) Nintendo Gameboy Advance SP
18) Nintendo GameCube
19) Odyssey2
20) Phillps G7400
21) PS1
22) Sega Master System
23) Sega Genesis (all three models)
24) TI994/a
25) Timex/SInclair 1500 (1000)
26) Timex/Sinclair 2068
27) TG16
28) Vectrex
Well, kind of close. I plan on adding the Nintendo 64 soon. Maybe Dreamcast - that would make 30! Still not 40 though... Oh well, at least I'm almost 3/4 of the way there!