Any chance of mentioning which fonts you've found to be truly free and which ones aren't? Obviously limiting the list to those already in addons you've examined, unless you're insane enough to post a megabyte+ list of all fonts ever developed that no one will ever read through. :)
I know I'm curious if my favorite fonts are good or if I should go ahead and look for alternatives.
Off the top of my head, a truly free font family that I know (and use) is the Bitstream Vera fonts. These fonts were created by Bitstream and released to the Open Source community:
The fonts have a generous copyright, allowing derivative works (as long as "Bitstream" or "Vera" are not in the names), and full redistribution (so long as they are not *sold* by themselves). They can be be bundled, redistributed and sold with any software.
I apologize for "making an example" of ClearFont3. I picked it since it's just getting started and this is an ideal time to evaluate its choice of fonts. I understand that it's never fun to take something "nice" away from users after an addon has been released.
Edit: If you're looking for more good quality open license fonts, I would highly recommend Linux Libertine as one of them. It's quite amazing, and has been extensively hinted for on-screen display.
Thanks for that link, I had not heard of that site before. In my UI prior to my account freeze (due to not have some spare cash thanks to the el crapo economy), I have been using the Bitstream Vera fonts as found on Gnome.org plus a couple of fonts on DaFont.com which come with licences that premit redritrubition. However I will now check out the offerings on this site.