Okay, so if FSX is more CPU dependent than video card, does that mean that the faster the CPU, the better it will run? Right now I'm using a P4 2.8 ghz CPU. Next week, I am picking up my new PC which will have quad cores, but they only run ar 2.66. I will be using Vista 64 Home Premium which I understand will sort of use more than one core. I know I will have more performance (because GeForce 260 and 4 gig of fast ram), but CPU wise, am I ahead?

Yes, you will be far ahead of the performance of the P4 CPU.