you're gonna have driver problems, all in all, I think you'll be fine with 32 bits..just tri boot with win 64, the 32 bit xp and the linux 64 bit
for end users, for now, not any real gain with the os
this is more for large Windows servers that are running into restrictions on how much work they can do, how many clients they can support, because of limits on the address space available for the file cache.
64 bit os's are operating systems that can use a 64 bit address space.
there'is nothing that prevents operating systems, applications, and database servers running on 32 bit platforms from using 64 bit integers for differant purposes.
basically the 64 allows better memory access also, "long mode" on amd64 gives you access to 64 bit registers, more general purpose registers, and similar things that'll help well compiled code.
also, benefits to the paged and nonpaged pools. With 48 TB of virtual address space, limits disappear.
none of this means much to us, and the os becomes just a toy for us to play with