We have tried a number of PowerPoint/Keynote presenters, but think we have found one now that we can whole-heartedly recommend: The Kensington Wireless Presenter with Laser Pointer and Memory. While the picture at the right shows a receiver/flash drive of only 1GB capacity, the product actually comes with a 2GB flash drive/receiver. The Amazon price is $52.82.
There is a lot to like about this simple presenter:
A criticism might be that the red laser pointer gets lost when using it on an LCD display, but this is true of all red laser pointers, not this one. If you are using a big screen LCD display in class, pick a green laser pointer. Most of us are not, however, so this one is just fine.
The device is powered by two triple-A batteries, so make it a point to carry extras, though I have had one of these for over a year and have not had to change batteries yet. A really nice design touch is that the on/off switch inside the device. It is triggered by removing or reinserting the USB flash drive/receiver. There is no external on-off switch to forget to turn off. You are not likely to forget the receiver, especially if you store your presentations on it, and inserting it back in the presenter turns the device off. Ingenious.
It operates in the 2.402GHz to 2.478GHz range, and is compatible with all recent versions of Windows and Mac OS X, including Windows 7 and Lion. If you are interested, here are links to the product brochure and manual, just in case you want to learn how to insert batteries in 11 languages, including Magyar and Polski.