Eh, start up the desktop and forget about metro. I like the look of the win8 desktop better than win7 aero.
Not a reason to upgrade, but after using win8 for a week it's decidedly not awful, and doesn't really feel like a step back. The inclusion of metro really makes sense for the convertible laptops, and I don't mind that it's also included on the desktop. I can see myself doing some stuff from metro and not starting the desktop if I am mobile and wanting to save battery.
You are in no way forced into the tablet optimized interface or the windows store. At least not yet
If you aren't on a laptop at all, well, metro is pretty worthless
Directx11.1 may not be a reason to upgrade, I still can't think of a compelling reason to upgrade, but I'm pretty happy with windows 8. It's nothing like the horror vista was.