The Logitech Wireless Desktop MK 300 appears to be another quality product from Logitech at a relatively good price.
The keyboard has all the basic functions you would need and expect plus a few programmable keys. One thing the keyboard does not have though is lights for things like caps lock or num lock. I realize this is to save battery power, but it is a minor annoyance as most word processors tell you things like this on the screen.
The keyboard is also pretty thin and relatively quiet, both of which are nice. The response to the keyboard is also very fast. Every now and then I think I catch it sleeping and it takes an extra half second to connect to the computer and follow my commands, but other than that it always seems ready to go.
The mouse is optical and feels like any standard mouse, it uses an invisible laser so no worries about children burning out there retinas by staring at the mouse. There is a small switch underneath the mouse to turn it off and on; which makes sense to have, for battery saving issues. Both keyboard and mouse take two battery's each and have lasted over a month of moderate usage, Logitech I believe says they should last 8 weeks, so that fits.
There is a USB based antenna you do have to plug in. It has a decent length (3+ feet) cord and a little button on the end for when you initially sync everything up to the computer. You do need to install Logitech's software to make it all work it is not plug and play. I didn't have any problems with installation or software. And as far as range goes I have gotten up to 25 feet without any problems, but your mileage may vary, do you apartment/house construction materials and what not.
So in conclusion if you are looking for a budget priced wireless keyboard and mouse with decent to good performance then I think you will enjoy this setup.