A co-worker of mine has Sirius radio, and it's pretty sweet. A ton of stations, and great tunes. They don't repeat like local radio, and have very few commercials...... Plus Howard Stern is a slight novelty... 
If you han't had a chance to lsiten to it, 
www.sirius.com gives out free, 3 day, web based trials. 
Anyone running it on their rig? How did you end up installing it?