I fully admit to bashing Vista, even viciously, before I had even actually got a copy to live with for a while. I repent.
I fully admit to bashing Vista too, and I continue to do so. It was pushed out the door unfinished and with poor driver support (thanks to Microsoft changing video architecture too late in the dev cycle, not due to any 3rd party failings) and while the driver issues have been resolved I still find Vista feels unfinished. But leaving Windows 7 off the good OS list is just wrong. Windows 7 is a well designed and executed OS, and Microsoft deserves credit for it. And I say that as a dyed in the wool UNIX / Mac OS X fan and frequent Microsoft critic. (Did I mention how bad I think Vista is?)
I have a theory that it's impossible to prove anything, but I can't prove it.