Temperature testing was conducted in a my computer system that I use on a daily basis, IE not caseless in the open air on a desk. The system consists of an Intel Core 2 Duo @ 3GHz seated on an Asus P5B Deluxe motherboard, 2GB of Crucial Ballistix PC2-8500 memory, two Western Digital 74GB Raptor hard drives... all in an Antec P182 case with an Antec NeoHE 550w power supply. The case was fitted with stock cooling, with all Antec Tricool fans set to low. Temperature measurements were monitored using RivaTuner's hardware monitor tool. Simulated load was produced using ATITool.
In changing fans and using our homemade cardboard shroud, temperatures improved all around. When using the inaudible (over system noise) 34CFM fan, temperatures were just a few degrees over that of the stock cooler running at 100%. With the 45CFM fan, temperatures were cooler than the stock cooler at 100%. With the slower fan, we gained most of the thermal benefits of the stock cooler at 100%, but with no audible difference in overall system noise. With the higher output fan, system noise was increased slightly, but the thermal benefits were the best.
For owners of the 8800GT who are concerned about heat and noise and want an inexpensive fix, I recommend doing what I did: swapping fans and making a shroud. Most enthusiasts should have atleast one 80mm fan lying around, whether it's in an old case or power supply, and if you don't, they should cost less than $10 each at your local computer shop. Couple this with some thermal paste to improve the subpar thermal pad placement, and you'll have a cooler card that will live a longer life.
What's also nice about this simple mod is that it can be reverted back to factory stock state quickly, and doesn't require any permanant modifications to your hardware. If you apply this mod to your 8800GT, or other video card for that matter, post a comment on your results. If you have any suggestions on other easy mods, let me know too!