i wouldnt even bother making a car p.c without a touch screen mate.
as far as a good set up its really up to how much you want to pay and how much work you want to do yourself.think ive spent about £400 on mine.that includes:
8 inch touch screen
motherboard and hard drive etc
special car dc-dc power supply(opus 150)
gps receiver
web cam(pointing forwards and records all the time

creative usb sound card(helps to have a half decent soundcard when its getting amplified 1000w)
wifi
let me know if you decide to make one as im more then happy to help