Ask Slashdot: How do you build a PC for the car?

Bruce Linley sent in this rather interesting question: "Whether it's an MP3 player or a GPS navigation system, what hardware is best suited for use in an automobile based PC? Hard drives must be tolerant of excessive vibration; the CPU must operate locked in a trunk where temperatures can reach 100C or -50C and where there is poor ventilation. The 12V power in the car may be somewhat dirty and variable. I/O cables may be subject to noise in long runs...and so on. Help me pick the components for the most rugged and reliable automotive PC!" Man! I would love to do something like this also! Comments, folks?