Re: I've posted the technical advantages of 64-bits that I see in engineering work. I also post anecdotal evidence.
So far, I've stressed numerous times that I am considering this from a consumer point of view.
Re: Will Core Duo beat a quad-core Opteron system? How about with 16 GB of memory?
I don't know about that, but I see Core Duo beating the dual CPU G5 systems. The quad core ones are a low volume niche, and the performance here has more to do with multiple cores as opposed to 64-bits.