What do audiophiles listen in their cars?

I know this is not a car audio sight, but it would help me out a lot if I could get input as to what the discriminating audiophiles listen to in their cars.

If you can give me a detailed list of the system, I would really appreciate it - I am starting an affordable Hifi shop that includes car audio.

Thanks a mill. in advance...
Not being sarcastic...
But on long drives, very often...just the engine, road noise and the wind.
I do all my listening at home as it is my passion but listening to music in the for me is distracting. I am a casual listener when it comes to driving. Half of the time I do not listen to music when in the car. Talk about room acoustics and noise in a car.......let's leave that for some other time.
Schubert, I attempt to look at it as free driving lessons. Still, after about 8 hours of free driving lessons it can get old. Being the clever fellow that I am, I have instituted the following rule. "Whoever drives picks the music."
So when the advice gets old, the Mahler goes in and the volume goes up. What, you are tired of Mahler? How would you like to drive?