I have a Microsoft Wireless Optical Desktop, which is a Wireless Multimedia Keyboard and a Wireless Optical Mouse 2.0, both are great. The keyboard sometimes falters a little, but I suspect this is a loose connection somewhere (shaking tends to fix it).

Battery life is long on this set, very long. I've had the thing since November 2003, and in all that time I've replaced the batteries of the mouse twice, and the keyboard only once.