When Microsoft released their remote keyboard for Media Center, I was excited.  Here was a wireless keyboard, including mouse and MCE-specific functionality.  As an added benefit, it uses the Media Center IR receiver so you don't have to connect another one.  It seemed to be exactly what I was looking for.  I bought one early but was very disappointed.  While I like the eraser-style mouse on a laptop (it's a shame they are disappearing), this one didn't work right.  It was very difficult to control.  It seemed that I could only get it to move a short distance with each push and it was really hard to center on anything.  Despite my wife's request that I return it, I kept it just for the keyboard part.  Now, I'm glad that I did.  I finally figured out the secret of using the mouse. 

There are two things I found make it a pretty decent mouse.  First, you need to turn down the pointer speed a lot.  This can be done via the Control Panel.  This allows for better control and centering.  Without it, I overshot the buttons a lot.  Second, you have to have the keyboard aimed directly at the IR device.  Anything in between, and it responds terribly.  With a remote or with the keyboard keys, you don't notice because you are usually only sending one command but with the mouse, you are sending a stream of commands.  This seems to make a huge difference.  With a good line of sight, and slow pointer speed, it's pretty useful.  I can even navigate the small buttons found on regular windows applications.

The one thing I still can't figure out is how to get the keyboard to work with my motherboard's BIOS.  I have USB keyboards turned on but no luck.  If anyone has this problem solved, let me know.