PC Atari is one of the most popular Atari 2600 emulators. It has nice design, fast emulation speed, supports all kind of Atari ROMs and controllers. It uses Sound Blaster or any other compatible sound card.

Stella is another popular Atari 2600 emulator, which was also ported on such platforms as MAC OS, Linux and OS/2. It is the main PC Atari emulator. It supports sound and all kind of ROMs emulation too. Windows version has pretty nice interface.

With this Mac version Stella emulator you can play your favorite Atari games on your Apple MacBook or iMac. It has all best features and possibilities of Windows version. Interface is a bit different, but still easy to use by any user.

Z26 is another nice emulator with cool vintage interface with retro fonts like in old school computers. It's available for Windows and MAC. Source code is available as well.