1001 Fonts offers a bunch of different fonts and a community that connects the creators with the users.
Abstract Fonts as the name implies contains all kinds of abstract and odd fonts
dafont offers a ton of free fonts in all kinds of styles and themes
Font Reactor is a database that contains some of the most popular fonts online
Font Squirrel has a large collection of high quality free fonts
Fonthead sales high-quality fonts and has some for free as well
FontSpace is loaded with fonts of all types
Nerfect contains fonts geared towards the comic book style
ShyFoundry sales and offers fonts for free
Simply the Best
"Simply the best as the name states, Simple the best has some of the best fonts known out on the web"