As for wireless keyboards...
why? Do that many people type with their keyboard on their
lap? A wireless mouse is understandable and almost
required. But a keyboard? What use would that be?
I just don't get it.
Even if you always type with your keyboard in the same position, there are still plenty of advantages over a wired keyboard:
1) A wireless keyboard comes in handy when you have your PC relatively far away from yourself. (e.g. to cut down on the audiable noise). Sometimes a standard keyboard cable can be a tad short
2) If you use your desk for other purposes besides using the computer, a wireless keyboard is a lot easier to put out of the way than a wired one
3) If you have a toddler around, there's plenty of other occasions where you may want to put the keyboard out of his/her reach, before it goes flying through the room.
4) No annoying keyboard cables laying across your desk, which can be in the way and add unnecesary clutter
5) For those using a keyboard tray (not me, that's the first thing I unscrew from a desk -- they kill my knees in a minute flat), you often end up with a keyboard cable that hangs down to the floor under the desk from extending and pushing back the drawer, and is likely to get damaged over time. No such problem with wireless.
To be fair, two downsides of wireless keyboards:
1) They require batteries to work, and when these run out (~6 months?) typing response becomes erratic until you replace them. Mine goes from working perfectly to becoming completely unusable within a couple of minutes when the batteries are empty, so not a lot of warning there.
2) To conserve battery power, very few wireless keyboards have LED indicators for the capslock/numlock/scrolllock buttons on the keyboard itself, although most have indicators for these functions on the receiver unit that hooks up to your computer's USB port. Many also come with optional drivers which can put little symbols in your systemtray to indicate the status of those keys.
I do dislike the majority of wireless mice I've tried -- since they require batteries to work, they tend to be a lot heavier than 'normal' mice. Some of the AA-battery models have an off-center optical sensor to make room for the battery compartment, which leads to unexpected behaviour and 'feels weird' if you don't always keep your mouse aligned straight. They also run out of batteries a
lot faster than a wireless keyboard does. the only wireless mouse I did enjoy using was the microsoft optical wireless wheelmouse that was bundled with the microsoft wireless keyboard, but unfortunately they keyboard blew chunks (no insert keys) and I didn't feel like paying $80 for just the mouse.