Dont go with the 32-Bit version of Windows, unless you dont mind buying the 64-Bit version later this year.
I've run both and I've never had an issue where a program or game will run on the 32-bit version, but not the 64-bit version.
Again, if you buy the x86 version, sure it will be fine for a while, but within this year you will want to upgrade to over 4GB of RAM (which you cant with a 32-Bit OS), and im sure there will be 64-Bit only programs out there that you wont be able to run.