Have some spare cash and I was looking to either upgrade my processor to the Q6600 or get the 8800GTX.  
 
My system specs:
 
Gigabyte P965-DS3
6gigs memory (a mix between crucial ballistix and G.Skill DDR2 800, Don't like mix and matching but works and overclocks fine)
Intel E6420 @ 3.2ghz  
8800GTS 320
Dual Boot between Vista ultimate and XP Pro
21" Monitor with res of 1680X1050
 
This system is a gaming system and literally I do nothing more than that. In which case I would lean more towards the 8800GTX because of its current price range of about 330 bucks but the Q6600 can be had for about $240.00. The 8800GTS I have still holds its own against all games even crysis I can run some high most medium at 1680X1050 but don't really know which path I should go down. I have about 350 bucks to spend.

video card for sure!3.2 Ghz E6420 should handle game pretty fast.
I have e6320 and x3210, both OC to 3.2 GHZ, the 3d mark 06 test score up 2000 points, but gaming is about same, since most game still use one core.

I have an E6750 @ 3.6 GHz and when I smacked that second 8800 GT in my system is was a much larger difference then when I upgraded grom my 5000+ BE.

I'd just save the money, but perhaps you're not as cheap\poor as I am.
 
I don't think the difference in performance will be worth the price paid.

With My 8800GTS 320 I score about 10200 in 3dmark06. I guess will it matter that much moving from what I have to the 8800gtx. I guess it would help as far as being able to increase FF and AA in games like Crysis but should I just hold off and maybe even just get the E8400 or 8500 (although I don't think my board can handle the new chips.

Honestly your more than fine with your current CPU.

Agreed.

9800GTX.  Only $299 @ the egg I saw yesterday.  Cant beat that with a stick.

 
Does that chipset even support Core 2 Quad?

 
I recently upgraded from a X1950 Pro (512Mb) to a 8800GTX. I smacked myself for not waiting a couple of months however. I think the price delta for the GTX is leveling off - now it has dropped massively in price in the UK. The 8800GTX is still a great card if you have the powersupply to handle it. I plan to go SLI in a month or two - riding the price wave. Especially as there is no sign of a newer card to touch it (like why is framebuffer size going DOWN on newer cards).
 
I can't comment on the performance delta between the 8800GTS (320Mb) and 8800GTX however I would imagine it would help quite a bit at that fairly high resolution (especially in Vista). I would reckon you could flog the older GTS card on Ebay to some sucker!!
 
Bob