Are you saying a desktop user wouldn't want to use windows 8 because of the Metro UI? There's only really one place where I ever see Metro on Windows 8, and that's in the start screen (which replaced the start menu), which is easily navigable using just a keyboard. In fact, I prefer the start screen to the start menu in Windows 7, Vista etc. because it's just a lot faster.
Anyway, I've upgraded one computer and this was a good reminder to go out and buy a copy so I can upgrade a second computer. I'm personally happy with Windows 8 in that for me the upsides outweigh the downsides. . . but for the sake of fairness I feel obligated to disclaim that I'm both more comfortable with adjusting my habits and more able to adjust the OS's behavior than many people out there.
Long story short, Windows 8 is both a impressive technical step forward and (for desktops) a stunning UI step backward. Which of those matters more is a choice for the individual.
Sorry, but I still think Microsoft screwed up by putting a tablet interface on a desktop OS. If they just had spent a little more time on how exactly they planned to get Metro on the desktop, things could have really been great.