Dan3: Interesting feature but your spinning still...
Win 64 is a patchwork mess. Enterpise does not like to deal with products like this: driver problems, hardware issues, software incompatibilities.
Frankly enterprise knows that Longhorn is the way to go but there will be a 32 bit version of that. So all this jibber jabber about 64 bits is just silly. Can you prove that kernel protection is really tied to 64 bitness?
And I don't know of any business that has said that it will be migrating all its client desktops to win xp 64(has AMD made a commitment in its own clients I wonder??? Want to bet that AMD doesn't walk the walk:).
However, that being said I do expect that the server and workstation versions will do ok. But there will still be a ton of 32 bit servers and workstations around...so this 64 bits or you go out of business rhetoric is purely fantasy.