I just paid $40 for the Humble Indie Bundle. Half of the payment goes to charity and the rest to the developers. I already have World of Goo but I’ll be downloading the other games for Mac and Linux.
Here’s a related article on the state of Linux and Mac gaming. I’m one of those gamers! 🙂
However, they haven’t yet taken the next step: once you’ve made a Mac version, indie games show that Linux users represent an additional 6% effective market share. Once you’ve created a Mac port and divorced your code from DirectX and other Windows dependencies, it’s not that difficult to port to Linux.