Yes, you can play MP3s (and possibly other formats) from a USB stick. My dealer and I did exactly this during our test drive. The command center even displayed album art. There are some command center bugs being resolved, so this may not work perfectly at the moment, but should be rectified soonMichael said:
You also forgot a few other sources: AM, FM and Satellite radio
For me, I expect it will be a lot of Pandora internet radio from my smartphone over BlueTooth