Joe, Re: the marketplace has decided that AMD64 is a superior instruction set to Intel's EPIC in Itanium.
It depends on how you judge superiority.
AMD64/EM64T represents easier reuse of existing infrastructure, making it easier to ramp in volume (keeping in mind, of course, that it has still not ramped beyond IPF, which currently has the support of ~2000 applications on multiple operating systems, including Windows).
On the other hand, this has nothing to do with the viability of the instruction set as a viable enterprise alternative for high end processing. I've been saying recently, based on Intel's actions and those of their OEM partners, that IPF is a better fit for higher end tasks, where the cost of converting infrastructure is small compared to the TCO of the solution. In these cases, the raw performance of IPF has an advantage.