I'm in the research and learning-from-others-mistakes/experiences mode, but I thought I would share some thoughts about hardware that I haven't seen in many newer cab ideas/builds.
If you stay in computers for any length of time, something eventually happens. It happens faster when you *do* computers for your job. You get tired of the excessive heat in that *one* room in the house; tired of the constant ambient noise of hard drives and case fans drowning out the silence of your last nerve; tired of 4000 tiny pieces/components it takes to build a computer just to check your email; tired of the monstrosity that attacks your your left knee every time you swivel in your office chair. These are all huge considerations for my someday cabinet (ne, for the future of my life outside of work).
With that, I'm considering the minimalist approach for computer hardware inside the cab. I know. I have a long way to go and an aweful lot of things to complete before I get to this final stage, but I think about this nevertheless.
How about a mini-ITX form factor with either a specially designed, integrated 1Ghz processor, or, if the games I choose need it, the same form factor with a P4 setup. They're hyper small, have all the hardware support you'll need (keyboard, monitor, mouse, memory, IDE port, sound, USB). Plus, you can find over-sized, 100% copper heat sinks that should keep them cool enough to function for hours and hours. You could probably build one if you needed to.
I don't wanna put it inside a computer case and just set it on the floor of the cabinet either. I'd rather mount it directly to one of the cab sides or a special mount (low and in the middle) with some kind of *very* flexible rubber material to keep it safe from the G-Forces of anyone becoming angry and kicking the cabinet, or the two or three times I move it. And, if I can figure out how to buy/build/power one, I'll have a 12-inch fan blade that rotates at 60 RPM and makes no noise at all just to keep a bit of air moving from the bottom of the cab to the vent on the top.
Instead of your standard hard drive, I'll use an IDE Compact Flash adapter and use a 2-4Gb flash card plugged right into the IDE port of the board. Heck, by the time I've done all the homework and am ready to put a computer in my someday completed cab, they'll be as big as 32Gb and cost only $200 USD. CF has a shorter shelf-life and, depending on your particular application, longer read times than an IDE HDD, but the trade-off seems worth it.
I know full-well that I will only use somewhere in the neighborhood of 150 roms on a regular basis (maybe more if I throw a "kegger"), and most of those roms will be of the "classics" variety requiring very little CPU horsepower.
Anyway, just a thought about my own personal vapormame cabinet. I'd love to hear your thoughts. Here's a couple of sites to check out as well.
http://www.mini-itx.com/http://www.mini-itx.com/store/?c=16#p2602http://www.multigame.com/CF.htmlhttp://www.computerworld.com/hardwaretopics/storage/story/0,10801,104582,00.html?SKC=storage-In2
EDIT: Wrong forum! Dang!