Flashrom, because they wrote a patch for my old motherboard so that I could flash my bios. I've always thought that if someday I have a lot of money I'd sponsor a few projects that I really like, maybe donate a few servers or something.
The Mono project. Or Banshee. Or Mesa3d. But probaby Mono.
Perhaps I could also contribute by creating levels for these FOSS games .
Coreboot probably, for flashrom and coreboot itself. Free us from buggy BIOS implementations.
Maybe AMD/ATI for their free drivers.
rockbox if they port to an iRiver E100
$10 is nothing, it will hardly help, if anything at all. If I was rich I would hire full time developers to work on projects like X.org plus donate $1M. I think my $10 will go to... xmms?