Hello! This is my page which holds open-source fonts I like. As you may have figured out, this page is set in Ovo, and this site is largely set in Sebastian Kosch's Crimson Text. Both of them are open source fonts with a variety of design influences. You can get them here and here. Although some free fonts are pretty crap, I like to think these are quite good.
Note that a few of these designs are basically similar-as-is-legal clones of paid fonts, like Arial is to Helvetica. They are marked with a †.
If you want more decent free fonts, here's a good list of open-source type websites - I personally find The League of Moveable Type to be consistently high quality, and the Velvetyne foundry produces lots of interesting and creative stuff as well. The Lost Type Co-op also does great fonts that are free for personal use. If you're looking for more retro or pixelly stuff, the Oldschool PC Font Resource is handy.