Streaming Music Recorder
It seems to me that this piece of software, when used with any of the subscription-based satellite radio services, would allow for pristine digital MP3 recordings of individual songs.
The Replay Music software automatically splits the streaming music into separate audio files and converts to MP3 format. It also adds identifying titles and artist info, and works with internet radio stations as well as sites like Yahoo! Launch.
If you enjoy online radio and wish you could clip some of the music for playback later -- it's certainly worth investigating.