A few years ago, before the introduction of hard drives in vehicle based navigation systems, most were DVD based. The Pioneer AVIC-D3 is such a DVD based system and shares its DVD drive for navigation and video/audio playback use.
As I stated before in the top five, since most use satellite radio or digital audio as an audio source, I don’t have much issue of the DVD being used as the navigation source. If a compromise must be made for value, this comes at a low cost.
Much like the bigger brother to this unit in the Pioneer line, the AVIC-D3 can be upgraded with a similar list of choices including satellite radio and traffic alerts as well.