Alternatively I have ripped copy of my CD library to a USB memory button which is plugged into the car radio. Being button style means it is not susceptible to being knocked as would a USB memory stick would.
I also have copies of my music on my laptop (in FLAC and MP3 formats as the master copies) my Android tablet (FLAC for best quality playback through my hi-fi) and my smartphone and PMP in MP3 format for listening to when out and about (there are several advantages to using a separate PMP rather than my smartphone).
BT Infinity 1 (unlimited)