Lifehacker has an interesting review of some of the Android GPS navigation apps available. Their top choice for turn-by-turn navigation ended up being the very lovely, Waze app. While I agree with a lot of the author’s comments on the pros and cons, I would add that Waze feels a bit too childish, geared toward my non-existent driving social connections, more than just telling me how to get around.
However, my favorite navigation app has always been the native Android GPS app, although CoPilot Live USA comes in a close 2nd. Fortunately, I was able to pick up CoPilot for a steal at $0.99 when they offered it about one and a half years ago. One of the benefits of CoPilot is the downloadable (albeit huge) maps for offline navigation.
I think the real-time navigation options for Android is awesome. I purchased a car dock for my Droid Bionic, and I love it.