64bit is the future... You may have a bump now & then with a legacy app, but in 2-3 years you don't want to still be riding that 32bit train.
Here is an easy to understand reason why:
Because they use MBR + NTFS to format drives, and the MBR spec has a limitation on the maximum addressible sectors, 32bit O/S's cannot use a partition larger than 2.2tb.
64bit O/S systems use the newer GPT format to partition drives and can (theoretically)_ address a volume up to 18 EXABYTES!!
Already today, 3 terabyte drives are available and 2tb ones are now quite common and cost as little a $90. You will soon want to buy a drive that will be larger than your 32bit O/S can see.
Also, the max addressible RAM for a 31bit O/S is 4gb.
A 64bit O/S can address up to 192gb. Depending on which version of W7 you buy....
•Starter: 8GB
•Home Basic: 8GB
•Home Premium: 16GB
•Professional: 192GB
•Enterprise: 192GB
•Ultimate: 192GB
Your next processor will have between 4 and 8 cores and need lots of RAM to feed the beast. Apps that take advantage of mega-multithreading will be 64 bit.
So.. your decision is this:
32bit app & driver hassles today
or
serious hardware limitations tomorrow.
BTW...
We all already went through this mess about 16 years ago as we transitioned from 16bit (DOS) and 32bit (Win 95... sorta, NT 3.51 for sure)
The numbers were smaller, but the problems the same... Legacy 16 bit apps & drivers having compatability problems with new 32 bit OS.
Go 64bit and buy at least Win7 Pro (for XP mode, and extra addressible RAM capacity)