Don't waste a lot of money on one.. if you want to go wireless, I have to recommend the
Logitech EX100 keyboard/mouse setup. It's simple and no frills, and goes for about $30 just about anywhere (Although I got mine a couple years ago on sale 50% off for $15 at Target).
It worked fine, and the batteries would last for a couple of months or more, but it is definitely no-frills, and the batteries always seemed to fail at the most inopportune times. I ended up going back to wired with a Razor Salmosa mouse (which I got cheap on clearance) and an $8 Microsoft "wired keyboard 600" which actually works great and feels very nice. I gave my wireless setup to my dad who is still using it with no problems at all.
I just don't see a lot of value in these $80-100 and up keyboards and all that. They just have a bunch of buttons that you'll never use and look all cool and fine but really you'll likely never use them.
THIS KEYBOARD would be cool to have though...