Yesterday I considered the unused keys on my keyboard. I got quite a bit of feedback - thanks! - and wanted to follow up.
Many people pointed out that the Windows key has other uses besides Start:
Okay, I admit it; those are pretty useful. The Windows key isn't quite in the same catagory as Scroll Lock. I guess I'll have to force myself to use it, and after a while it will become second nature.
Speaking of Scroll Lock, Liron Shapira pointed me to Scroll Lock is the most Unappreciated Key. I definitely don't appreciate it :)
As far as useful keys which are missing, here's the consensus list:
What's cool about this is that an enterprising keyboard manufacturer could add these keys without requiring any software support, simply wire it so Help=F1, Copy=Ctrl-C, Cut=Ctrl-X, Paste=Ctrl-V, and Undo=Ctrl-Z.
Finally, a correspondent proposed a "blog this" key. Now that would be useful!