Wee Free Icons
I'm talking about the little images - not the star people everybody goes crazy about. Anyway, after having used the Silk Icons for what seems an eternity (they are good you know) it was time for something new.
The Fugue icon set not only surpasses the Silk icons in sheer number but also includes the source Photoshop files and a guide to mix and match the Icons.
Definitely the best icon set I know - for now.