I'm running an 8800GT... And I'm wondering whether I should get another one for SLI or whether I should get a 9800GTX+. I'll be getting a 20" LCD monitor as well if that makes any difference. I haven't used an SLI machine before so I have no idea about any possible stability or compatibility issues. Can anyone tell me if it would be worth spending less for possibly more?
Nope. Not at all. Played UT3, Crysis, HL2, CoH, Spore, COD, FEAR2, WIC and many others without a glitch. I also had one 8800GT while I was playing in a 19" monitor and then when I upgraded to a 24" I added the second card willing to have the same performance of the 19" but now in a bigger screen. In a nutshell, this was what happened, except that in some games I got even better performance with the SLI in a 24" when compared to the single 8800GT in the 19" screen.
Just make sure that your PSU will handle the load, keep your drivers/games updated and make sure your new screen will have a resolution of 1680x1050 or higher... Just for testing when I run the SLI set up in my old monitor the benefit is not so nice when compared to the 24" monitor.
It's doing a such a nice job that I am having a very tough time in justifying an upgrade for now. Probably I will stick with it until something really revolutionary comes up (like a Dx11 card or something). And, even then I will still save one 8800GT just for Physx...
If you look the Tom's Buyers guide you will see that one of the top choices even for 1900x1200 is a pair of 9800GTX+ which, roughly, is what I have and you will have.