its not they money that matters, its the thought that counts. If you have a million dollars please by all means go ahead and commercialize open source. But when you are that quiet developer doing a small project that noone donates to and one day you receive that 10 bucks, you feel pretty damn good.
Kaffeine, wine.. Those names come to mind. Note that not all projects have options for donations. DBAN, linuxtv, mplayer and last but not least ffmpeg also come to mind but do not seem to have options for donations.
Oh well, just donated $20 to Kaffeine and $20 to wine. I know, that's $40 together and not $10.