The most accurate z80 emulator. Has almost perfect emulation and has proper IRQ line handling (unlike most other Z80 emus). In addition to arcade emulators it is also used by Pasofami (Nintendo NES/Famicom) and DGen (Dave's Genesis/Megadrive emulator - the guy who did DTMNT and Final Burn).
GNGEO A Neo-Geo emulator for Linux. Sorry but I can't list the games that are supported here in CAESAR. It would be a huge amount of work to work out the required ROMs without CRC information in the emulator and I don't have Linux to do proper testing either!