Ric Molina, writing for MacGamerHQ:

Many seem to be under the assumption that there are no good Mac games. Sure, that was true a few years ago, but a lot has changed since then (Can a Mac be a gaming PC? is a great read). Turns out that 7 out of the 10 most-played games on Steam have a Mac version, and all the best indies support the Mac too. These top Mac games will show you how far Mac gaming has come.

Pretty impressive list. My favorites are all on here (including FireWatch and Braid), but there are many that are new to me.