Ran across this article by Nathan Ford,
Applying Macrotypography For A More Readable Web Page which I thought was very well done. It addresses important basics on where to be cautious in your font choice and where to let loose, considerations for line-height as well as the best line length, tips on helping your text stand out even on a busy page, and suggestions about color choices.
Ford also makes an excellent point about the “pretty” of the web page. That the intention is to create a page your viewers will enjoy reading (without squinting!). That’s primary. Once you have a readable layout, it’s up to you to provide your so-very readable text with a pretty layout.
Always keep your target audience in mind—the older the viewer, the bigger the font-size! *As I creakily push my glasses back up my nose…*