The first nice option is Minion/Myriad Pro combination (see previous post), but the fonts aren't open... just free for personal use. Another nice option is the Cambria/Cambria Math but there might be licensing issues since they require MS Windows on the Machine.
The free fonts with equivalent metrics to common fonts are another good option. There's a list of other free fonts also. Matching maths used to be a problem with XeLaTeX, though now the mathspec package makes this easy by allowing one to mix and match symbols and fonts together with simple commands (as shown in previous post for MnSymbol).
OpenOffice has some nice fonts install too... FreeSerif and Nimbus. Charis and Gentium are also good but don't have Small caps support. Fontin has won alot of praise but didn't blow me away. Asana Math doesnt have Italics.
I'm not satisfied by the current choices for math symbols either. Latin Modern (XeLaTeX default) math is nice, MnSymbol is ok and Cambria is very nice but not free.... sigh... the search continues.
Shakes - L3mming
EDIT: Some more great links to font list.
- Beautiful High-Quality Free Fonts For Your Designs
- 15 Fresh High-Quality Free Fonts
- 15 Beautiful High-Quality Free Fonts
- 20+ Beautiful Free Serif Fonts
- 40+ Excellent Freefonts For Professional Design