Okay, here's another question. Here in Solaris world, all 64-bit really gets you is a larger memory addressing space. We've been 64-bit at the OS for a long time, but the OS can run 32-bit and 64-bit applications. All the 64-bit applications buy you is a larger memory addressing space, at the expense of slightly slower runtime. (After all, now it constantly has to deal with 64-bit numbers instead of 32-bit.) As such, virtually all applications are still 32-bit, except for the ones that really need to address more than 4GB of memory. In many cases, they provide both.

Anyway, what does 64-bit buy you on the Windows side? There have been Wintel computers for quite some time that have been able to address more than 4GB of system memory (I assume there's some sort of paging algorithm being used), so I'm not sure what 64-bit gets you.