Really all depends on cost and what you can get. Ideally i want to get rid of my cd/dvd headunit, and 3 gauge din holder and put a 7" touch screen in there, so it will need vga input with a usb output - for the touchscreen functionality. It will then be connected up to a craptop (laptop that is well, crap) that i got from work for free, which will be connected to my haltech ecu so i can get read outs - woo rice, and play music, gps, etc etc of a carpc.
I have been looking at these lilliput screens. I am looking to be setting my carpc and car interior retrim up around the end of the year, performance mods first - which is almost done, around september/october time.