argh the decisions, here's the situation i've got a p4 3.0c which i could sell to someone for an almost new price and get a a64 3000+. assuming i go a64 do i get 512mb of corsair xms 3200xl or 1gb(2x512) of kingmax ddr 500 (i havent been able to find the bga version anywhere

), or on the p4 side 1gb(2x512) of kingmax vs corsair 512mb(2x256) ddr 500. if anyone has had any personal experience it would be greatly appreciated.
ram wise i wont be able to afford to put in than $200-$250