I own the Microsoft Natural Multimedia Keyboard. It's a good keyboard, very solid and pressing down keys feels nice. I've never really used the hot keys, so the "Multimedia" part is kind of useless to me. I do like how the arrow keys are in a triangle shape instead of the diamond shape like the Elite version had it. It's only a PS/2 keyboard which meant I couldn't use it on my laptop which had no PS/2 ports.
The only real complaint I have about it is the function keys aren't F1, F2, F3 etc. by default. On boot, they default to Cut/Paste, New, Open etc. You have to press Fn Lock to use the F1, F2, F3 keys everytime you startup. This is slightly annoying as I turn my computer off when I'm not using it. If you can tell me how to get Fn Lock on by default, please let me know!
It's a good keyboard, well worth the money. Remember there is the OEM and Retail versions of the keyboard. They're almost exactly the same, but the OEM comes with a dark grey trim and the Retail version comes with a blue trim.
BTW, I own the Original MS Natural Keyboard, MS Natural Keyboard Elite and MS Natural Multimedia Keyboard.