Windows only: iTunesControl, a free iTunes add-on, adds two killer features that make open-source player AmaroK so appealing—namely, seriously customisable universal keyboard shortcuts and a pop-up on-screen display with album art and song information. Some of this functionality is offered in other add-ons (see Adam's list of 23 great ones for examples), but iTunesControl is a preferred choice for those who really like to control their music. You can assign play/forward/back-type commands to nearly any key, including Function-switched keys for laptop users, and have the display pop-up anywhere on the screen, in any font/color/line combination you'd like. Better still, iTunesControl can be anchored to iTunes itself, starting and stopping whenever you launch the music app. iTunes Control is a free download for Windows systems with iTunes 4.6 or later only.