Legit Reviews posted a comparison review beteen the AMD 5000+ Versus Intel E6600. Here's a taster:

Our testing showed that when gaming at high resolutions the limiting factor is not the processor, but is actually the graphics card. This was shown to be true in three out of the six games that we benchmarked. We used the ATI Radeon X1900XTX graphics card, which is the fastest single card GPU on the market (not counting the NVIDIA 7950GX2) and comes priced at a healthy $499 so it's not like we put in a weak video card by any means. The reason we didn't run X1900 CrossFire is because how many people can really afford it to start with? Most gamers we know still run a single GPU and no physics card! We tried to make our testing go along with what marketing data has shown in recent months.

The bulk majority of gamers run resolutions of 1280x1024 or lower and for this group of gamers the Intel Core 2 Duo Processor E6600 won five out of the six games when tested at this resolution. In the benchmarks where the processor mattered like Comanche 4, Far Cry and X3 Reunion the Intel processor was able to show clear advantages versus the AMD competition.

So after running these benchmarks it's clear that at 1600x1200 and the eye candy enabled the GPU is the limiting factor right now when it comes to gaming performance. With the next generation ATI and NVIDIA graphics solutions already taped out and due for a launch later this year we should be seeing better gaming performance before Windows Vista starts shipping.