Due to appearance, most of us like the single-DIN Marine products from JVC, Kenwood and Clarion.

My car is an SE with aftermarket interior so I went with an RD660 JVC head - but that does not give you navigation.
I will be VERY surprised if you can find anything with Navigation worth buying. As far as CD, AM/FM, MP3, etc., those are easy. Many units even support a Satellite radio add-on.

Hopefully, someone will prove me wrong on the Navigation thing.....................