Screen: 7" xenarc touch screen, the new ones are bright, well built and made specifically for a computer in a car. The normal warranty is one year, but if you take it out of the housing to mount it, they still warranty it for 30 days. http://www.xenarc.com/product/700ts.html I will turn on/off automatically when power is supplied/taken away.
For the power supply, get an OPUS. If you have the money, dont bother with anything else. They are made just for carputers, have built in protection from completely draining your battery and automatically start up and shut down with the car. http://www.opussolutions.com
The quality of the CD/DVD/radio are probably all gonna be about the same. I don't have any specfic recommendations other then to go with external USB devices so they are easy to mount where you want. Since these are all hooked into your computer you can easily control them with the built in equalization features that come with windows and your sound card drivers.
For the sound card I would go with the external Phillips aurillium, its sound quality is awesome, just as good as the external Sound Blaster Extigy NX, but doenst come with the infrared remote and the big plus, powered completely off of the USB port. If you have the space inside your computer case I would go with an interal Sound Blaster Extigy.
For the iPod just run the output into your computer's sound card's line in and you can just control the volume form the computer's volume control.
XBox: The easy solution would be just to put in an AV switch to switch between the computer input and the XBOX input. If your the type with too much time, money, and computer skills on your hands you could probably get a video or TV card with video in, run the XBOX's output to it, then get a relay card http://www.mpja.com/productview.asp?product=6074+KT that would be hookup up to the xbox power switch to turn it on. This would require some code to work the relay and switch the video input on, but you could then do it completely through touchscreen control.
GPS: CoPilot is my favorite, I think it has the best interface for in car use, but it is expensive.
Originally Posted by h22lude