Why in the world would I post something about publishing Windows games? Well because Unity, which I've mentioned on Download Squad before, is a Mac-only game developer tool. It just might be the only Mac exclusive game engine/authoring tool that is now a switch hitter. Besides, as their site points out, wouldn't it be nice to publish your games for an audience that is rabidly pro-gamer? When people ask me whether to get a Mac or PC I often ask them if they'll be doing a lot of gaming. There's a distinct advantage on the PC when it comes to games (chess notwithstanding).
Not only does Unity provide a one-stop shop for animating, rigging, and programming 3D games, complete with a physics engine, it also publishes Mac games (duh), Windows games, Mac web games (via plug-in), Mac Widget-based games (pretty much needing the plug-in again), and soon Windows web games... I really dig the Unity vibe, and I know that they are the David in the Goliath battle scenario. So if you're interested in making games, or know someone who is, give 'em a looksee. It's easier than you think.