Which graphics card for my PC upgrade?

Hi all,

yet another semi-nub asking which graphics card would go best with my set-up without being bottlenecked by the rest of the system.

Currently running (never bothered overclocking as I've never needed to):

CPU: E6750 @ 2.66Hz (thinking of upping to Q9550 - reasonable price point currently...)
RAM: Corsair PC6400C4 x 4Gb
MoBo: P5N32-E Sli Plus - http://www.asus.com/product.aspx?P [...] templete=2
GPU: Leadtek 8800GTX
HDD: 2 x WD Caviar SE16 320GB in Raid 0 (1Tb WD Green 32Mb cache storage drive)
PSU: Seasonic M12 700

(Samsung 226BW 22" monitor, also thinking of upping to 24/30" )

Originally spent a good month or two agonizing over the setup back in 2007 - went with a good mid-level setup aiming at most compents being at a decent price range just before they started going up exponentially, the only thing I really treated myself to was a nice high end GPU.

I've been toying with the idea of picking up another 8800GTX to run in Sli, but even second hand they're going for almost the same as a GTX 260...

Anyway, down to business - currently the crappest thing in the system is probably the CPU, hence the potential upgrade to the Q9550, and although I have truly loved the 8800GTX, I'm a little upset that there are games out there that it doesn't run smoothly on max settings...

Again trying to stick with the value or money theme but still going for as high performance as the system can handle - What cards do you suggest?

Feel free to add as much detail as you like regarding pros/cons, stats etc. If you disagree with another's suggestion, please explain why.

Anyway, thanks all for your time =))


PS feel free to point out any other holes in the system and potential upgrades - not looking at rebuilding a completely new system, just adding a couple of things to keep it slighlty up to date.