Well, server parts are generally robust, which is good, but if this is in a 1U rackmount, you aren't going to get an 8800GTX in there. The PSU is probably not built with the output or connectors for a high-end video card.
I dont see any reason why an 8800GTX wouldnt work in it as long as you have an adequate power supply that would have the correct power connections and the board didnt limit the space for an 8800GTX to actually fit in the setup, but I ran an older server setup several years ago with AGP and found that I ran into quite a few problems with gaming. I couldnt tell if it would happen with this or not. What is the deal? How much would you be paying because if this isnt an absolutely GREAT deal then I would just jump on a regular LGA775 board and drop a Q6600 in it. Your games will not benefit from dual quads at all and it is possible that you could see stability problems with the setup while gaming. These are mostly just guess's not based on fact. So my advices is that if you are getting a great deal that is to good to pass up (as in if it doesnt work out then it wont set you back much) then I would get it. If not I would just build a rig more designed for your needs. Hope this helps!
Well I am getting all those parts at 600$ wich I say it's a pretty great deal, they would normally cost around 1500$, if I buy it I will just add my 320gb baracuda and i will try to find a case that fits the card, and my psu is a 700w seasonic, will it handle 2 quads and a 8800gtx?