I have a battery powered Dremel which is good for light work, but I wanted a rotary tool with more oomph. I decided to take a chance on the $13 WEN Variable Speed Rotary Tool Kit. This thingsis crazy powerful and fast. I used it to rough out some wooden spoons I made this weekend:
It comes with a bunch of bits, sanding discs, polishing pads, and mandrels. It also has a keyless chuck spindle lock that you can turn by hand to swap bits without a wrench.
For a few bucks more you can buy the the same tool with a flexible shaft. I just bought that one, too!