Via Stylegala comes a post by Lois Knight on Typography Essentials. I have been toying with a rule-of-thumb for simplifying web-typography. It's not what I'd call fully tested yet, but it has been working well enough with the students that I've had try it. Here it is:
The rule of twos: No more than two type faces, two colours, two point sizes, two line-spacings and two weights.
Of course you should break this rule, but when you don't have the time, energy or inspiration such rules of thumb can be useful. Oh, it's still in beta so send me your feedback.