ok these i know are available for definite:
every nintendo console/portable apart from the gamecube- the n64 emulator plays most of the early games no sweat but the bigger newer games (stuff like perfect dark) may or may not play and if they play may not look right- or be slow/jerky
every sega console/portable upto the megadrive/mega cd/mega 32x (may be a saturn emu but not sure about that)
Every atari console.portable upto the jaguar, and there is an st emulator too
Every commodore console/computer upto the amiga
Turbo grafix/pc engine
Coleco consoles
playstation 1 (not many games work 100%- and you actually require a bin/cue file rather than the actual cd)
think thats about it