So the first benchmark I ran was 3D Mark '06. I had to lower my CPU speed a little to 2340mhz (223x10.5), but the rest of my system specs are same as in my signature.
I didn't realize the free version of 3DMark '06 was so limited in terms of usable settings.
It would only let me run the benchmark at 1280x1024 noAA noAF, and my result was 3839 3DMarks. That seems a little low, but I've never run any 3D Mark version in years. I think my system is probably starting to show its age, as its an older nForce2 Ultra platform.
From a purely subjective point of view, my games have become dramatically more playable. Need For Speed Most Wanted framerates must have more than doubled from what I got with my x1600Pro, and I now can play with all of the graphics settings maxed out. I get much more consistent frame rates on HL2:E1 with 4xAA + 8xAF at 1280x1024. UT2k4 is MUCH faster even at 1600x1200 with 4xAA enabled.
Also, I feel I should point out that my AGP bus is running at 83mhz, giving a effective bandwidth of AGP 10x... still significantly less than PCIe 16x, but every little bit helps.
I'll post some more actual benchmark numbers after work today, but for right now I'm very satisfied with the in-game performance boost the card has given me.