Looks good to me, the E8400 is a nice budget CPU that will allow you to overclock. You want to aim for around the 4Ghz mark and the E8400 can reach that when it's overclocked. Another option is the E8700 as you might not want to run the machine overclocked all the time. I'm no expert on it but it does create more heat in the chip which is a problem in an arcade cab if there is not sufficient cooling. Check out BYOAC as there are a few threads over there about overclocking. Also don't forget you really need to get a 64-bit OS too. Either XP 64, Vista 64 or Win7 64. You get a substancial boost running the 64-bit compiled version of Mame. 2 Gig RAM running in dual channel mode is perfect and 500W PSU should be ample. You might want to consider a nice big terrabyte drive too as its very easy to fill up drives on a cab. The video card sounds fine also. One final thing I don't know how well they cool their cab's but I have two beefy fans with variable speed dials that blow air out the back of the cab just behind the PC. I also keep the lid off the PC and have an air grill just behind the monitor. It's important to keep the air flowing.