I built a system about a year ago for my Honda Accord. I bought a power inverter from Walmart. I ran the power switch up to the front of the car, hidden under the steering wheel, to turn the box on and off. I used Windows 2000 and Hibernation mode for quick start ups and shut downs (25 secs avg.). If you are worried about spikes or overtaxing your car battery, go with a SFF system (less power draw) and use a UPS backup. Those raise costs, however, so it just depends on what you want to put in it. I also used RC Car shocks to mount my HDD to absorb road shocks. Thas was the unique part of my build that I haven't seen anyone else use, and in about 9 months of using the system I never had a bad HDD sector. For the LCD screen, I bought one from a local auto sound store and mounted it in the console between the front seats. I ran a wire underneath the carpet to the fuse box under the stearing wheel, it only drew a few hundred milliamps. I used a RF mouse to control Winamp.
