I was thinking about putting a GPS in and I found an Eclipse (not sure of model) that replaces the whole stock faceplate and takes up the whole space. It is not a flip, the screen mounts in the stereo spot with buttons surrounding the screen for CD, radio, GPS, DVD, etc... I like it because it is not the flip-out kind and it looks like it supposed to be there.
they are good if you go on a road trip and want to know where gas stations are and such, and also to find your way around other cities. but i agree they are pretty useless in your own towns, you should know how to get places.