I've tried some of these tweaks but only found the bAllowScreenShot=1 and bUseJoystick=0 to be useful. Increasing the range at which decent textures or more trees drawn seems to drastically reduce the performance on my system - ranging from 9 FPS to 20 FPS outdoors.
At the moment I have the default oblivion.ini with the game settings maxed out, 8x AF at 1280*1024 and I get a constant 30 FPS outdoors. I would have hoped for better performance - I hope nVidia can get something out of their hat to improve it. I would be very interested in seeing some benchmarks (e.g. 7800 GTX vs 7900 GTX, SLI vs Single).
I've still got a few more things I can try - I would like to play the game