If you're a big fan of radio and want predominantly US channels, then you'll probably love RadioRocker,
RadioRocker contains over 5,000 stations from across the United States and is perfect for US citizens that may want to listen to a special broadcast or sporting event in another state or town. RadioRocker takes the format of a car radio allowing you to assign presets (although only 6) in the player window. You can click "Manage Preset Buttons" in the "File" menu or use Command+P to set them.
There are a few drawbacks though. Not all channels are available at any one time which can be due to streaming problems or simply that the channel is not broadcasting for a while. Also however, you are limited to listening to just one hour of each station - if you wish to continue listening after this you have to pay 10 dollars to upgrade to the full version.
RadioRocker is ideal for US listeners wanting to listen to radio stations across state or who simply love American radio.