Evo,
ORAC is correct, you will not see any benefit going to PCI-E for the Vid card, since we only just filled up the bandwidth for 4X AGP and 8X AGP has more than enough bandwidth for the next gen Vid Cards. Going PCI-E now gets does get you ready for the future though.
If you are going to go with "The Dark Side of the Force" (Intel), I would look at the 925X Chipset. It is the current leader for PIVs.
Personally I would look at the new 90nm Socket 939 Athlon64s. They are the hottest thing on the market and the first CPUs have hit the market at a sub $200.00 price. Put that with an nForce3 250GB or one of the new nForce4 Ultra/SLI mobos (Will launch Oct 19.) and you have a PIV killer on your hands for less money.
Take Care,
Richard