Don't shoot the messenger; I'm just reporting what some posted what MS said on the tech tour, which is currently going through west coast (started in Chicago). This was reported by someone who was at the Irvine event.
I don't know how reliable the info is; so take it for what it's worth, or what you want it to worth. Believe it if you want to, don't believe it if you refuse to; I'm just passing along what I have heard.
Originally Posted by erratick
M: Longhorn will only be 64bit
It was quite clear from the presentation that Longhorn was to be 64bit only for server and workstation product and very likely (like I said only some hemming and hawing) to be 64bit only for the Home class product.