I know that you guys usually play MAME emulators, but I found my self playing Raine emulators most of the time. It has a small library of games, but the games are good, including WWF Wrestlefest. The emulator is also less buggy and runs perfect on older DOS computers! You could probably run this on a 486 and definitely a Pentium 133mhz + cpu. Personally, my favorite arcade emulator.
http://rainemu.swishparty.co.uk/
I would like to see someone port this to Dreamcast or for the Wii system homebrew.