Need some advice regarding upgrade and video card.

Hi there. I've just ordered a bunch of new parts, including:

3.2c P4 Processor
2x256 Kingston PC3200 Dual Channel Kit
P4P (non-deluxe) Motherboard
Seagate barracuda 120gb 7200rpm SATA drive

I'm upgrading from a 1.8ghz P4, P4T-E with 2x128mb of 800mhz RDRAM.

My question is I currently have a GeForce Ti4600. It was a very
expensive card when I bought it a few years back (Not expensive now, I
know I'm definately going to be upgrading my video card within the
next few months when the newer ATI and Nvidia models hit and the
current ones drop in price. I'm a casual gamer and like to play a lot
of the latest games. I know the card only has DX8.1 support, but I
also realize not too many games use DX9 yet, and even those that do,
don't fully utilize is. My question is, should I see a decent
performance increase by upgrading the rest of my system? I debated
buying a new video card now, but decided against it, due to my budget
+ the fact that I *know* cards will be dropping in price soon enough.
(I spent $695 Canadian on my Ti4600 two years ago and since then, have
decided I will *never* shell out that much cash for a card again.) Any
input would be greatly appreciated. Thanks!