I'm thinking CDs with MP3 files on them, not an iPod. I did see a Pioneer unit that has a single CD and a cassette player. It'd be nice to have the cassette AND in-dash CD changer with the ability to read MP3's, but such an animal doesn't seem to exist. If I have to pick between losing the changer or the cassette, I'd rather lose the changer. Another option is a single-DIN head unit with a cassette player that can control a separate CD changer, and there are changers that can read MP3's. But then I'd lose glove box or trunk space for the changer, and I'd rather not have to deal with an external changer. Yes, I'm picky