Joachim Breitner's Homepage
I just discovered the nice Survey of Free Math Fonts for TeX and LaTeX (PDF-Version) by Stephen G. Hartke – a good overview of the common font packages, with examples, useful for those who have seen enough Computer Modern by now.
What I’m still missing is a good style guide: When should I use Palatino, when is Utopia a good choice? What are good reasons to use a sans-serif font for the text, and when is that not a good idea? They all look nice to me, but I doubt that the professional typographist leave it all to personal preference.