I use a panasonic pcmcia cardbus sd reader which seems (and should be) faster than usb, limited only by the card write time. This handles the audio fine. I suspect that not all other readers will interface with the jukebox software and handle audio, though technics, midi and pictures should be fine, but have not tried any other readers yet. The next laptop will have a sd slot built in, hopefully that should handle audio ok since toshiba are one of the systems original developers.
The plug ins will give sx6 type functionality with the superior tlx lyrics (which I much prefered) in the screen and should be much better on the tv screen too and also twenty six character file names.