Although EM64T is pretty much the same as the AMD 64 bit stuff, the other part of your comment is false. Core Duo is not in any way a copy of AMD architecture. Intel got sidetracked going after MHz/GHz for a while. Core Duo is based on (with enhancements) the older Intel Pentium III architecture, not AMD's architecture.
True. Intel, for example, does not put the memory controller on the CU die. I did not mean to imply that Intel stole or reverse engineered AMD's internal workings; I just meant they adopted AMD's philosophy.
There are advantages and disadvantages to Intel's memory approach. Intel can take advantage of improvements in memory technology without redesigning the CPU, but The AMD Opteron can have an independent bank of memory for each physical CPU. There are already servers on the market with 16 Opteron CPUs. Intel will eventually have to adopt this architecture as well, in the server market.