You're in business if you have the hardware to support it. I asked about 32 vs. 64 bit when Win7 RTMed. From what I could find, it appears you don't really get any gain with 64 bit until you hit 8 Gig RAM.

>Everyone I've talked to got the 32-bit Version of Ulimate 7 and the Key for it (BUT - I've been told the key WILL work with the 64 bit version.... so.... if you can get your hands on a 64 bit version THEN you will be in business with the key!)