Unless you have a another system, don't have a lot of unsupported hardware, or are willing to dual boot I would not recommend XP 64 because 64 bit driver support simply isn't out there yet.
There is also no support for legacy MS-DOS and 16-bit applications. If you have an older application that runs in MS-DOS mode or is a 16-bit application It will not run, or if the 32 bit program has a 16 bit installer the program will not install.
Windows XP Professional x64 Edition doesn't support 32-bit drivers! So unless your hardware has 64 bit drivers they will not work in XP 64. From what I can tell, most vendors are not working on 64 bit drivers for older hardware and some of the newer hardware still doesn't have 64 bit drivers.
XP 64 seams to run alot of aps ok, However, with the lack of drivers and the problem with playing media files/dvd's as well as gaming running slower, I would not recommend XP 64 at this time.
The Good
The Bad
Most 32 bit programs run fine.
Most apps seam to run faster.
Boot Time Seams faster.
Not enough 64 bit programs.
Slower FPS in 32 bit games.
Not enough Driver Support. 32 bit drivers will not work.
16 Bit Programs will not run.
