I'm looking to build a new PC over Christmas due to the annual hardware price drop that occurs this time of year, and a question sprung to mind when browsing OS's. Microsoft Windows Vista 64-Bit Business for System Builders Single Pack DVD - OEM http://www.newegg.com/Product/Product.aspx?Item=N82E16832116211 Microsoft Windows Vista 64-Bit Home Premium for System Builders 3 Pack DVD - OEM http://www.newegg.com/Product/Product.aspx?Item=N82E16832116205 Why is the Business edition so much cheaper? What's the catch there? Also, I will be using 4+GB of RAM, so the 64-bit is necessary. Thanks in advance from an OS newbie.