I'm sorry F0d Man, but seriously...I think when someone lists reasons for upgrading, they would be reasons someone somewhere actually gives two craps about (no, that's not meant to be taken literally, but you do get my point). That's not to mention that any improvement in Vista came along with utterly horrifying performance (yeah sure you might not have experienced that, but you can be certain the majority of users did), outrageously high requirements, and constant unnecessary hard disk usage.
[end rant]
Unfortunately, Microsoft still has a strangehold on the PC market, and no one has, as yet, came up with a model that provides enough advantages over Windows, and is a widely known, that the average Joe would consider switching.
Ehtyar.