Linux Mint for the FLOSS Fund
Linux Mint is an Ubuntu derivative but instead of just repackaging Ubuntu with a different art work, they improve on Ubuntu while being compatible. e.g. if you search for help on a problem the response that applies to Ubuntu also applies to Mint
The whole OS feels cleaner, the packaging of the media codecs is not encumbered by US laws and I just like the menu.
In my humble opinion they have already solved many of the paper cuts that Ubuntu is trying to solve.
(pnijjar: The donation page is here: http://www.linuxmint.com/donors.php