Is it possible to configure X to allow for the use of the Windows Key as it would be used in Windows XP? For example, I'd like to be able to press it alone and have KDE's K menu pop up, or WinKey+D to show the desktop. Possible?

Just go to the KDE control panel > Regional and Accessability > Keyboard Shortcuts and set up whatever combos you want. The winkey should be recognized just like any other key. Many individual apps can also have personally shortcuts defined in the same way.

It's a little more complicated if you want to make sure the key can be used in other environments. You have to use xmodmap to set up new keyboard mappings or somesuch. I'm not sure how all that works though.

At least in Gnome, going to System->Preferences->Keyboard Shortcuts allows you to use the "Linux" key for anything. I have it configured to lock my computer when I press it, but it could be assigned to any of the other options. The key assignment appears as "Super_L". If you selected the open applications menu item, and pressed the key, then you could make it open the menu. By default I am not sure if it does anything.

I am almost certain that the KDE keyboard configuration tool would allow you to do the same thing; although I don't frequently use KDE.

The configuration is dependent on your window manager, X does not really care about stuff like what keys you are pressing (it just sends the key presses off to another program).

Thanks. That did the job wonderfully.