Here’s an interesting gadget. It’s an FM transmitter from Logitec that can play back MP3 or WMA files from your USB device to your FM stereo. It’s obviously only for your car, unless you have some way of connecting a DC car outlet in your house, but I’m not sure why you would wan’t to.
You can also connect it to a mobile phone for charging. In case you’re color coordinating, it comes in six variations.