I would not really go to extreme on a card because some of the latest offerings have a programmable chip which as of now could be considered a overkill because how many software developers have took advantage of this..Not many and future devlopment will take a long time Unreal II took years to finish..by then when games or Sims are updated to make use of this technologies I see no need now. Plus software developers look at the compatibility of the masses and not the few..look at the system requirements of RF..

A good CPU like the Athlon XP is beter than a Duron due to the L2 cache-like a P4 is somewhat better than a Celeron..
But in all honesty a good 1Ghz computer with a good card and memory would very do..I only built the 3 Ghz system because I knew it would last a long time (years) before needing to upgrade and it was really sorta just more of a novelty to build it..I did it myself reasonably..the GeForce GPU is more complex than some of today's CPU's