If you don't have 1 GB of hard drive space for Descent 3, you'll need a CD-ROM to play the movies (and to access data files on a bare minimum install).
Pioneer's DV-AX10 model also comes with the ability to play SuperAudio CD discs - a format developed by Sony and already commercialized that is battling with DVD Audio for the place as the successor to compact disks.
Unfortunately, the N64 version doesn't include nearly as much commentary, because the cartridges have limited capabilities compared to CD-ROMs. But on a PlayStation or PC, you'll be treated to great commentary after every big play.