We've seen plenty of Tricorder-styled gizmos, but the PMP-09 is the best I've seen, and a functional gadget in its own-right. The flip-up PMP has a 2.8-inch display, 8GB storage, and provides 12 hours of music/4 hours of video playback.
It has 12 different Star Trek LCARS (Library Computer Access/Retrieval System) interface themes, and the site says more will be available for download. File format support is listed as MP3, MP4, AVI JPG, BMP, and WAV.
What got me into a mini-nerdgasm was seeing that beyond the TR-590 Tricorder X-style design, there are also Medical, Borg, Marine, Workbee and Troi-styled models available. The starting price of $US349 might bring you back down to earth though. [AmeralisGrafx — Thanks Junior!]