What is the difference bwteen the actual Retail Version and OEM? I don't really know the difference between the two. Could you please elaborate? Yeah, I tried one out in a local computer store here, and I loved it! Vista Ultimate 64bit because it incorporates everything you get in Home Premium and Business, but some sweet little extras! Yeah I want 12GB. I've heard that with some things 6GB can strain a little bit. So may as well temporarily futureproof my system to 12GB until my next big upgrade! Thanks for your advice!