I prefer Logitech brand for keyboard and mouse. I personally have the wireless G7 and OMG, that thing Owns big time. I love the on the fly mouse speed adjustments. The weight is perfect and glides over any type of surface. I really recommend the G7, but it cost a little more. You get two rechargeable battery packs so you're never out of juice.
For the keyboard, I have the wireless S510 Logitech. Super thin and lightweight. Very responsive. You can't go wrong with Logitech products. Programmable keys and such. Good features.