The CPU is important for gaming, but it's not like he's running an old Celeron here. To me, regardless of the small gaming increase, the overall system performance increase with a Core2Duo would make upgrading to one worthwhile so long as the current board supports it.

What video card are you running? Chances are you'd get alot more gaming performance by just throwing $200 (or whatever) at that instead. Type "dxdiag" in the Start -->Run... window and look under the display tab.

{edit} Nevermind, I see it's an x800... Upgrade that. Go with the advice in the post above.

My budget would be somewhere around 500 dollars tops. That's already a buttload of money im willing to throw into my computer.

My main issue is that I can't afford to upgrade my computer often. What I do now has to last me for about 2 years. So while Pentium D is sufficient now. It might very likely become obsolete in a year.

Here you go, my system specs are as follows:

Processor:
Intel Pentium D 820 (2.80GHz)

Motherboard:
Intel D945GCZ

Memory:
DDR2 1024 MBytes

Graphics Card:
Radeon X800 Series
256 MB
----------------
Anything else?

Upgrade your ram from 1 gig of ram to 2 gigs then get a 320 Geforce 8800 GTS for that budget.

But that still leaves me with the Pentium D issue... What are you guys' thoughts on that?

The Pentium D should be just fine, it is no slouch even though it's no Core 2 your CPU still got 2 CPUs witch should last you antore year or two.

According to Intel's compatibility chart, your board can't support a C2D processor. Adding a new motherboard would increase the cost at least another $50-75. You could probably stretch a couple years out of that Pentium D and just get some more ram and a really good video card.

Add 1 or 2gb of ram, and buy an 8800 GTS 320MB. That should make you quite happy while gaming compared to your current setup.

One thing to keep in mind though is if you really want to stretch your video card $$, the nvidia 9 series cards (9800GTS, etc) are supposed to be released very soon (in about 2 months). They say they really leave the 8 series cards in the dust performance-wise. Could be worth waiting a couple months on buying the video card and just buy the ram for now.

That Nvidia 9 thing sounds intriguing, is there any price estimate so far?

The new lineups are usually fairly similar in pricing to the current lineup, add maybe 10-20% for the first few months. A super high end 9800GTX might be $600-$700, where the more down to earth high end card like a 9800GTS would be $300-$350.

Waiting for the next generation also has the added benefit of forcing 8 series price cuts, and an 8 series would still be a good option.

Oblivious how do you know the 9 Geforces are coming soon?

It's the rumored release date. It's also said Nvidia may be aiming to release a new series in Q4 of every year.

Here's a random hearsay thread on the 9 series. Here's another thread. Pinch of salt optional...