I mostly use scrapbooking fonts by Kevin and Amanda to decorate design elements (headers, buttons, sidebar titles, etc.). For signatures, I especially like the fonts in their Fonts for Peas line.
Have a specific font that you'd like to use for your elements that is not featured here? Email me. Chances are I have it or can get it easily. :)
At this time, I only use Century Gothic and standard Blogger fonts for post and sidebar text.