Moil,
I'm not going to quibble over cpu benchmarks because it's an argument for retards. I will however say that every single review and comparison of the core 2 duo vs. A64 shows the core 2 duo is faster in almost every single test or benchmark in what I consider to be the three "major" categories of multimedia processing, general application usage, and gaming. There are always a few benchmarks that show the A64 out ahead, but they are few in number and generally only applies for specific programs, not entire categories of software.
I have an A64 X2-4400 and it's very fast, but a $300 core 2 duo cpu would be about 20% faster in almost everything I do, including CD/DVD ripping/encoding, video editing, and gaming. The only thing keeping me from buying a core 2 duo system is that my computer is already plenty fast enough so even a *free* core 2 duo cpu wouldn't be worth it since I'd have to buy a new mobo, memory, and video card. But if I need to buy a whole new system today, there would be no question in my mind that a core 2 duo system would be the absolute best option today.
6-9 months from now when AMD starts sampling native single-die quad cpu cores, then it might be a different story. But we're talking right now, and right now core 2 duo is faster, period.
As icing on the cake for those who care about such things, core 2 duo also uses less power and people are getting massive overclocks out of them using generic air cooling. The current A64 chips just don't compare. They're both fast and neither is a "bad" choice in my opinion, but the core 2 duo is better in almost every measure.