VICE - Bring loops to life with the loop slicer plugin for Mac and Windows.
jGameBase - jGameBase is a fully-featured retro-gaming emulator frontend and game database utility.
Frodo - Frodo is a robust Commodore 64 Emulator for the Macintosh.
Z26 - Z26 is one of the best emulators for the Atari 2600.
GameBase - bu22.com - the home of the GameBase frontend and databases.
WinUAE - WinUAE is a Windows port of the emulator UAE.