As far as software emulation it depends on what system that people want to emulate. If it is the more classic video game systems and computers of past, then I use the MESS emulator hands down. MESS emulates everything from the Timex Sinclair to the Vic 20, TI99/4a, Atari 2600/5200/7800, up to the NES/SNES and Jaguar and everything in between.

If it is for more modern systems such as the PS1 on up then Mame it is. The one nice thing about the MESS emulator is that it runs on DOS, Windows, Mac, or Linux. I can build a fast and inexpensive Linux machine that runs MESS rock solid or any of the other OS's if you don't mind paying for the operating system.

Regards,

Brian