Anythingbutipod: Riding your bike with your headphones plugged into your ears could be dangerous. If you would rather not live on the edge, there is a solution for you. The Hammacher Schlemmer bicycle MP3 player mounts to your handle bars and pumps out tunes through its built-in speakers.
When not on your bike the MP3 player detaches from the speakers so you can use it as a typical portable player. The internal memory is 1GB but can accommodate additional SD/MMC memory. The player connects via USB and is UMS compatible so it will work for both Mac, Windows, and Linux.
Price: about 100 euro.