(Update:6/26/02) I have finally upgraded the computer system. (horay!) I used an old Dell case, and replaced the motherboard/cpu. The result is a Duron 1.2Ghz processor, 256mb of RAM, and an OEM-ATI Raedon 7500 card with TV output. Getting the TV output to work correctly took a little bit of tweaking, but it looks great. The system is capable of playing all games including all of the latest NeoGeo games, at full speed. This is MUCH better than the P166. ;)
The only problem I have now, is that the new motherboard is not compatable with the Dell powerswitch. Also, since it's an ATX motherboard, I cannot simply leave it on and let the power strip turn it on with everything else. So... until I have a permanent solution to this dilemma, I simply ran the "power" pins from the motherboard to an extra Happ button. To turn on the PC I simply click the button. I REALLY hate this, but for now I guess it's ok.

(10/21/01) Currently I'm running an old Compaq Pentium 166MMX with onboard video, SBLive soundcard, 2x CD-ROM, 64MB of RAM and a 17" monitor. Not a powerhorse by any means, but it sure does play a mean game of Punch-Out!
Updated 10/21/01: After playing a few newer games on my P166, I realized that I will DEFINATELY need to buy an updated PC to make this arcade machine really rock. (Groan) I guess I'll have to ask my CFO (aka wife) for more money to get this upgrade. :)