well I got an MSI K8 neo4 Platinum mobo; an AMD 3500+ CPU; an ATI x700Pro vid card; 1gb of corsair xms ram running at 2-2-2-5 1T. The graphics arent up all the way but I punch out an average of 55-57 fps and the game looks sweet.
Also I built this pc over a year ago and the partts were mid to high mid performance wise. I spent around 1300 for it and for that price now you can get a much better system.
If you want some general guidelines for pc parts, get at least a 256mb vid card, a d@mn good mobo like a dfi lan party or asus, along with an opty 165 or a dual core athlon 64 around 2.2 or 2.4ghz. some corsair xmx or ocz ram. That basic set up will put out great resluts on games (I'll ball park the price at 1500 on the cheaper side) but as new stuff from amd and intell are soon to come out who knows what will be better on the top end.