Uber should forget about the 32 bit versions. I noticed a few new AAA titles coming out this year are no longer supporting 32 bit. It's dead, so lets just let it go.
To understand the memory limits on the different OSs and versions visit this page http://tinyurl.com/68ywlv4 Win 7 Home Premium is limited to 16GB on 64 bit but thats because its the Home premium (Average use) Windows 7 Professional 64Bit - Win7 Ent 64bit support up to 192GB of memory. These 3 versions are for the power users and businesses.