The Nikon D1 is also an outstanding value. The one annoying part of the Nikon is that they are very selective in the selling over the web. The most interesting camera is the Kodak DCS330 with the Nikon Prolinea Body. Remember the older versions still have the 1.5 Med pixel CCD there are lots of these for sale on E-Bay. A tiny magnetic platter spins around and stores the data.
Flash memory is all solid state so there are no moving parts.
The best choice depends on what brand is most compatable with your camera. How you use your camera, and your budget. The hottest microdrive is the new 1Gig microdrive from IBM,Sandisk, Lexar, Kingston, Microtech, and Simple also offer great products. It can hold over 400 images at the highest resolution uncompressed. I just plug in the USB to my MAC G3 and its there like another drive.