The Ultimate Edition only have a few extras that honestly I doubt many will use. So Business should be fine for most people, although personally I'd get the retail version so you have the choice of 32-bit or 64-bit.
As there are some apps that don't run in 64-bit mode, then again there seem to be more than don't run in 32-bit but run in 32-bit emulated.
On the flip-side of this however is that drivers are generally less supported on 64-bit Windows. tbh there isn't really any benefit from being on either one over the other. get whatever you feel like getting.
if Windows 64-bit actually was as big a leap as Windows 95 was to Windows 3.1x then I'd probably not be using 32-bit but as some apps don't like 64-bit mode I'm sticking with 32bit for now.