You can always overclock that Pentium 4 641 as they are utter monsters for OCing, the Cedar Mill 631 still owns the world record for the fastest CPU ever at 8.1GHZ!
hmm well i can allways add more ram later. but the main issue i need is to find out what video card to get now does that 8600gts seem better than the 7900gs or should i just go with the 7900gs?