You really only lose overclocking abilities by going OEM. Just ignore anything out of a Dell optiplex for 478. Those tended to be riddled with bad caps in my experience. The board used in the Dimension 4600 is a great matx one that can be found cheap.

Dell boards are pretty solid and I have never had any problem with them as long as they have good caps. Later 800 fsb dell boards are a lot better in my opinion, good caps 9 times out of 10. It was always the 400 fsb boards that were always bad for me or I've just had crap luck. I only have 1 3rd party socket 478 board and its a late asrock p4i945gc. I can't overclock my p4 3.0 ht past 3.3ghz, probably because the voltage control is joke. It does have pcie which is a nice. So If you want to go down the overclocking path, find a good asus board with good voltage control and a stable vrm. Or dell board is as basic as it gets and it does what its made for, no problems with the ones I have.

Thanks. I think I'm going to go with the Dell board. I could get my P4 3.0E up to 3.5 very easily on my Abit board, but to be honest I didn't notice much difference in performance. This system is definitely a period piece and intended to stay within its limits as far as games go anyway.