TotalTunes

Interestingly enough, TotalTunes is one of the ultimate in iTunes interfacing. It allows you to do searches, Last.fm integration, Coverbox changes, Growl notification, the works. It even allows you to set up keyboard shortcuts to do playlists, controls, or anything else you might want to do with iTunes.

Pretty neat little thing, although it's pretty much only for MacOSX. So Windows users, sorry, you're outta luck. Again.