I recently switched over. OS X is a nice, clean OS, but its not the next coming of Christ that some people make it out to be. I never really had any trouble with Windows (used many a version). Sure, it may have taken me one extra click to do something or disable some annoying little feature, but I consider myself fairly computer competent, so it took all of 1 second extra to do. Maybe thats why OS X doesn't seem as 'revolutionary' to me.
I do like the easy installation of programs (no registry to worry about, etc). I love the interface and shiny buttons (I'm kinda superficial sometimes).
In the end, if tomorrow, the whole world switched to either Windows or OS X, I wouldn't really care.
Also, Vista seems to get a bad rap by a lot of people. It seems that their opinions are based on the first 30 minutes of using the OS. After you disable UAC (three clicks?) and get your firewall permissions settled, its a solid/nice looking OS.
Also, Apple, I've found, is not as 'innovative' as they (and their supporters) claim. A lot of their features are simply third party apps that are just integrated into the OS (Dashboard, Spotlight). Although, I have to give them props for at least doing that.