I have a 500gb external USB hard drive that I bring inside, fill with my taste of the week, and plug into my car stereo. (The only caveat is that is has to be formatted as FAT32, but that may be a Ford Sync System thing.) Do you have any idea how much music 500gb (465gb usable) is? At 4 megs per song, (math in my head at 2:30am - lets see, 100 songs is 400mb, 200 songs is 800mb, 250 songs is 1gb, 250 songs times 465 usable gb) that is 116250 songs. (Someone please check that math.) That is around 113 hours of music without hearing the same song twice. For perspective, if I could drive straight through, I could go from my home town of Akron Oh to Seattle (35 hrs), then to LA (17 hrs), then to Miami (38 hrs), and back to Akron (17 hrs) and still have about 6 hours of music left. I doubt I could find 116250 songs I care to hear, but the math is fun.

Or you could just use Sirius XM satellite radio... laugh