Yes, I do!
I try as much as possible to use free fonts. (Both in terms of free beer, and free speech.)
I like kp-fonts a lot but I have a few gripes about it: (i) as far as I know, it's Type 1 only, which is great for LaTeX and PDFs, but not for embedding in webpages or ePubs, (ii) it's really pretty similar to Palatino.
Lately my favorite has been the Linux Libertine series:
This is a very attractive font for printed text. Yes it has a true small cap.
For e-reading, however, it has a sister font I like to use called "Linux Biolinum", which actually reminds me a lot of Fontin, but overall I find it more subtle. The "fanciness" of Fontin gets to me after awhile.
That's quite beautiful.
As their names imply, these are open source, GPL-licensed fonts, and are available in type 1, and true type, and open type (with some opentype glyph variants you can use in Xe(La)TeX.
And no, you don't
have to use linux to use the font, though it helps...
Homepage for project:
http://linuxlibertine.sourceforge.net/