
I found this post over on Codename Revolution detailing the best selling consoles world-wide. Here is the list:
Sony Playstation 2 - 120 Million* (shipped)
Sony Playstation - 102.49 Million (shipped)
Nintendo Entertainment System - 61.9 Million
Super NES - 49.1 Million
Nintendo 64 - 32.93 Million
Atari 2600 - 30 Million
Sega Genesis - 29 Million
+Sega CD - 6 Million
+Sega 32x - 200,000
Microsoft Xbox - 24 Million
Nintendo GameCube - 21.66 Million
Sega Master System - 13 Million
Sega Dreamcast - 10.6 Million
NEC TurboGrafx-16 - 10 Million
Sega Saturn - 9.5 Million
ColecoVision - 6 Million
Intellivision - 6 Million
Panasonic 3DO - 2 Million
Atari 7800 - 1 Million
Neo Geo - 1 Million
CD-i - 570,000
Magnavox Odyssey - 340,000
Atari Jaguar - 250,000 (first-year recorded)
*Currently selling in the market as of December 2007
This list is surprisingly lacking the Nintendo Wii figures, but its still a fun list anyway. My grandparents had an Intellivision when I was growing up. Oh how I remember Dungeons and Dragons on there.