There's certainly no shortage of them for the Mac, although I'll readily admit you can't get all the same ones you can get for the PC. Our friends at MacGamerHQ.com have rounded up their list of ten of the best.
MacGamerHQ has restricted the list to actual commercial releases, not "pay to play" games that have become popular. No one should want to get nickled and dimed just to play a game.
First-Person shooters (FPS) are poster boys and the Mac unfairly suffers in that department. Everyone just assumes that the Mac gaming platform is lacking because it doesn't support the latest Call of Duty or Battlefield. But the Mac still has many great First-Person Shooters to offer, including some of the very best.
Games on the list include BioShock Infinite, Team Fortress 2, Deus Ex: Human Revolution, Portal 2, and others, and includes links to the Mac App Store and Steam, where you can pay for and download these great games.
Of course, what made this old school Mac gamer happiest was seeing Marathon on the list. Marathon was Halo maker Bungie's first big success (not their first game, however) and was revolutionary. You can still play it on modern Macs thanks to the Aleph One open source project.
Check out the list and let me know what your favorite FPSs are