We recommend Logitech's Coreless MX Duo mouse-and-keyboard kit on the strength of the mouse alone. Wireless, optical, and rechargeable, the mouse brings all of the benefits of untethered input, and it reduces battery juggling, one of the technology's biggest drawbacks. At $99, you'll pay a bit more up front, but you'll make it back in what you don't shell out to Duracell.
Upside: A rechargeable wireless mouse is such a good idea that we're surprised we haven't seen more of them in addition to Logitech's MX 700 Cordless Optical Mouse, which comprises half of the MX Duo kit. The mouse also includes thumb-side front and back Web navigation buttons that feel totally natural, and the page-scroll-lock and task-switch buttons framing the scrollwheel aim to reduce finger stress and help streamline work flow. The keyboard has media buttons, complete with a volume wheel and hot keys for e-mail, IM, and various Web pages--not to mention an additional scrollwheel and back button on the left side.
Downside: The MX Duo's $99 price is a bit expensive for a keyboard and a mouse, but you should be able to find the Duo for less if you shop around online. Some less nimble users might also have problems with some of the scrollwheel buttons on the mouse, which have been criticized by some people for awkward placement. Also, left-handed users are forced to adapt to the mouse's right-handed ergonomics.
Outlook: Wireless, optical, and rechargeable--sounds like love to us. The Logitech Cordless MX Duo is a common inclusion in high-end desktops, and we confess, it's the very same mouse that aided the assembly of this review. Once your thumb lines up along the forward and back buttons, you'll wonder how you ever did without them. The biggest question is the initial investment, which we feel is a small price to pay for this smart design.