Design is important, and nothing is perhaps more important than how we present our text. I previously wrote about designing logos: Logo of Letters. KISS or NOT?, but this time I stumbled upon a rather in-deapth post about choosing good text type (fonts): 15 tips to choose a good text type written by Juan Pablo De Gregorio. (Many people have recently dugg this guide and spread the word, although the actual post actually is from two months ago.)
My personal experience is that you have to think of the big picture during the whole process. Avoid mixing fonts, unless you decide to mix them on purpose to create an effect.
Sherif Taric has a little section called Design Matters: Fonts, where font families are explained, and it further suggests some rules on using fonts.

That’s a good find.
I’ve added it to my Del.icio.us bookmarks for later…
I have followed many of the tips intuitively before, but I always enjoy finding the reason behind.
[...] If you continue to surf a little on Smashing Magazine’s pages there are a lot of nice posts to be found. However in both cases with these types don’t forget: Choosing Better Fonts… Bookmark this post:These icons link to social bookmarking sites where readers can share and discover new web pages. [...]
[...] net. Five hundred fonts are rather overwhelming, and I will have to point you in the direction of Choosing better fonts…, before you “overload” your computer with rogue [...]
boring/unhelpful