I can't figure out why cars come with CD players when they could put a USB port on the front of the thing and allow me to play hundreds of songs without fiddling while driving.
A record button would be nice too so I could pull songs off the FM when I happen to get a good station. The record would put the last minute of music and everything up to when I push the stop.
My car stereo has precisely that feature as well as an Auxillary in for MP3 players with no built-in USB.
My MP3 player has a "switchblade" style USB port that pops out of the bottom of it. I searched for one that had that feature. I had a very early MP3 player (RCA Kazoo) that I really liked, but I lost the USB cable and replacing the special cable cost almost as much as buying a new MP3 player so I never did. I learned to always get an MP3 player that doesn't require a cable.
I listen to my tunes in my MP3 player and when I get to my car I just plug it in to the car stereo. It charges it and I can access my tunes and listen to them on the car stereo.
It isn't the greatest car stereo in quality, but that feature sold me. It was only $150 and it is made by VR3: