To Serif Or Not Serif

Douglas Bonneville talks fonts:

Putting these two together creates an unwanted conflict in the design. Trade Gothic wants to get to the facts, but Bell Gothic wants to have some fun. This kind of tension is likely not part of the design goal, and should be avoided.

Lengthy piece on combining typefaces. I've always had a love / hate relationship with selecting fonts, made even better / worse by the likes TypeKit.