Applications built in LabVIEW 32-bit will run on Windows 64-bit - including server editions. I have LabVIEW applications installed on servers running 2008 R2 and 2012 R2 and they work fine. This is true of pretty much every 32-bit application.
I do all of my development/deployment of 32-bit applications to PCs running 64-bit operating systems.
Unless you *need* the memory that 64-bit LabVIEW grants you, there's no reason to use it and lots of reasons against using it (not being able to run it on a 32-bit OS, limited driver/toolkit support etc.)
LabVIEW Champion, CLA, CLED, CTD
(blog)
