well for vista you really want at least dual core and 2gb ram, like i said, windows 7 runs on a smaller footprint. MasterP ran win 7 pro fine on his netbook (1.6ghz atom, 1gb ram, 160gb hdd) and said it was definitely fast enough to be usable. So yeah I mean any power user will want a dual or quad core with lots of ram but its not really necessary to run win 7.
