What I want in a car “entertainment system”

I’ve been thinking about building a PC for use in the car for ages (most likely running some flavor of Linux). Gradually the market is catching up with my desires and it looks as if soon I may be able to buy exactly what I want “off the rack”. Here’s what I want:

1) A touchscreen interface that fits a double DIN dash opening. (common in many late model cars)
2) Provisions for (2) 3.5″ Hard drives. I want all of my Mp3’s in the car.
3) The ability to accept any cell phone’s SIM card and work with a “douche tooth” earpiece.
4) Obviously 3G/4G connectivity, Bluetooth, and WiFi.
5) GPS with turn by turn directions.
6) Alarm System

This is all I can come up with now. I’m sure I’ll be adding to the ‘wish list’ as time goes on.
Does anyone out there have any experience with, or opinions of, these type devices?
Share in the comments.