Is this possible? I have one machine running MS Windows Media Center and one machine running Vista Premium. I do not want the info between the computers to be the same as they are used by two different people. The desktop with Windows Media has a 250 GB HD with about 40GB of data on it. The other machine has a 160GB HD with about 20 GB of space used. Can I do this and if so how big of an Ext Hard Drive should I look to purchase? Thanks