Ok, I am finally actually getting started on setting up my own MAME system, although it's been years since I first played with MAME. I've gone through and picked out most of the games I'm interested in running (about 150 or so) - most all are pre-1990 games and I don't think there's a single ROM that is over 1M. I'm mainly interested in the classics like Donkey Kong, Moon Patrol, Ms. Pac, Frogger, Galaga, Centipede and games of that era.
I am either going to be building a cabinet or using an old gutted one (not one that will land me in the Hellcade), and right now my intention is to keep it as close to that arcade feel as possible (buttons with leaf switches, trackball, spinner, joysticks, and possibly some sort of real arcade monitor like a Wells Gardner, etc). In other words, I'll probably be doing a good bit of shopping with Suzo-Happ.
Right now though, I am on my first step - picking up a computer. I'm leaning towards running WinXP SP3 since I've heard it's fairly stable and probably offers the most choices when it comes time to pick a front end (although Linux doesn't scare me as I have a Unix background).
So my first question is, how powerful of a system do I need to run the types of games I'm interested in as faithfully as possible? Would a P4 do the trick? How much memory? I'm not looking for serious overkill, and trying to keep the price down as much as possible.