Yes, I like computers, no doubt about it. For a while now I've been entertaining the idea of building a small computer using a mini-itx motherboard. The only thing holding me back is that I really couldn't do anything with it that would be worth building it for, save for the fun factor.
I could possibly use a tiny computer in the car (or in my case my truck). There are already computers available right now that will fit exactly where the car stereo goes, like the Xenarc CP-1000 (it's discontinued - I'm linking it just for demonstrative purposes). No fuss, no muss. Pull out the car stereo, install the computer where the stereo used to be, outfit with a 7-inch touchscreen and that's basically it.
The question remains, what would I use a Car PC for?
To watch movies? Nah. Sorry to say but you can't get that much of a movie experience from a tiny srcreen.
To listen to music? Yeah, I suppose.. but probably not that often.
To do computing stuff such as with e-mail and so on? No. Since you have to be stationary to do that stuff anyway, bringing a laptop along does the same job.
GPS? Yes. I would use this for certain. Having GPS on a 7-inch screen is very, very nice.
Engine diagnostics? Absolutely. On GM vehicles (I have an '05 GMC Canyon) there is a connector called OBD-II (which I think means On Board Diagnostics). Software exists right now that will connect a laptop to the OBD-II port, and it will tell you more than you ever wanted to know about your car. Graphs, meters, gauges, you've got it all. And it would be oh-so-sweet to have that stuff right in front of you on a 7-inch screen.
But at the end of the day, it's really not worth it to do it.. at least not for me. I already have GPS and while the engine diag's are cool, it really doesn't justify the cost of installing a computer in the car.