Why would you post benchmarks from the manufacturer? We all know they are spun to hell and back. Let’s start looking at independent benchmarks.
I gave up on believing that G5’s were a faster machine than a similarly priced Intel box a year ago. Sure there were tasks that it would beat the PC at by a large margin, but there many others that it would come up short. I went Mac mostly for the advantages of the OS and the best editing solution (FCP), which was exclusive to it. Speed advantages came from better interaction, not raw horsepower. Saving two minutes on a render was easily lost by a crash, or difficulty figuring out the interface.
The Mac experience will not change at all when an Intel chip is inside it. I think product updates will be more regular, availability will be stronger, and Apple won’t continue to fall behind in the mobile computing sector.
My biggest worry is how SSE3 will fair compared to Altivec, and how tough it will be to translate over.