Video card: Forget Sli and get a 8800GT or if you're can afford it a 8800 GTS512. Performance is better and there are issues with SLI.
CPU: The new C2D processors E8300, E8400 (price/performance) and E8500 are the one to get. Phenom are way too slow for now for the price.
PhysX card: it is already dead so if you want to waste your money. No game will make full use of it.







