Gave Sirius a test-drive over the weekend. Their music channels were not bad at all. But the talk stations were surprisingly lame--the political channels were predictable "liberal" vs "conservative". With commercials.
I tried to test-drive XM Radio, but I couldn't do load in the "plug in" for the 30 day free trial.
So, I did a last round of testing with Rhapsody On Line, an internet only music service. I found the sound quality as good as that of Sirius, and a lot better than that of Yahoo Music Player. And Rhapsody's many "radio stations" are way better than those of YMP and they have a larger number of focused stations than does Sirius. They even have a Hawaiian Music channel, which this Hawaii-phile really likes. I am listening to legendary Hawaiian performer Israel Kamakawiwo'ole while I type here.
I signed up for the plan that allows me unlimited listening via the computer and on a supported MP3 player. Rhapsody it is!
Plus, by not going with Sirius, I don't have to be part of the station that is known primarily for being the home of the lame Howard Stern.