I've had a computer mounted in my car trunk for about 3 years now.
Its a standard MicroATX tower. Using a standard desktop IDE hardrive. (Maxtor 20GB). Its used solely for mp3/ogg/wav playing purposes.
The hardrive is still going strong after 3 years without a single bad sector (I do a full surface scan with ScanDisk at the end of every month to check for bad sectors)
The case is laying on its side on top a 12" thick piece of foam, its then strapped down to my trunk floor with 3 rubber tie down straps . This setup allows the whole case to bounce around a bit with bumps. Laying the case on its side also puts the hardrive vertical in relation to the road. This prevents shocks from making the drive's heads slap down on the platters.
For control/display I am using a standard 20x4 HD4478 compatible LCD. OS is a Win98. I'm using Winamp with a plugin called VisLCD (something like that, don't remember exactlly what it is called) that drives the LCD and provides a numeric keypad control interface.
The display and keypad are connected to the computer via a very long parallel cable that takes the same path through the car as the factory rear speaker wiring does. (there are 25 wires in a single parallel cable, this is more than enough to carry all the signals for the LCD, keyboard and audio out + plus power for both keyboard and LCD

)
The display is mounted in my dash where the factory CD player would go. I left the keypad laying between the front seats.
In the 3 years I've had this setup I have had only 2 major problems. When I first built the thing the case was mounted directly to my trunk floor without the rubber straps and without the foam padding. After about 2 weeks with this setup the entire drive cage assembly ripped from the case frame. It crashed into the motherboard damn near cracking it in half. (hardrive survived though!) My second problem was my inverter buring up for no apparent reason.....
Any questions don't hesitate to PM me
