Doom 3
Speaking of software that doesn't like NVIDIA hardware, here's something that does.
X800 256MB is easily a match for 6600 GT, by virtue of extra resources dedicated to accelerating a separate depth pass for rendering. The clock speed difference is balanced by the extra vertex and fragment hardware.
The same is true with X850 PRO and 6800 GT, the NVIDIA board having more of what it takes to show the Radeon how it's done, despite some 150MHz less core speed.
