The biggest change of Windows 8 is the Metro interface. While the Metro interface is good for a tablet, it’s not designed for desktop computers. I upgraded my main workstation to Windows 8 a while ago. I use the desktop about 99% of time, and I only use the Metro interface when it’s necessary.
I found that if you have multiple monitors, you can configure it so that Metro only shows on the second monitor. This works very well, and the interface does not interfere with the applications on the main monitor. Here is how to do it.
This activates the Metro interface on the second monitor. From now on, whenever you press the Windows key, the Metro interface will show on the second monitor. Note that this change only applies to the current session. You’ll have to do it again the next time you log on.