I really appreciated my Android phone when we were down at the shuttle launch, for many reasons, but the best of which was the built in Google Navigation system. It got us around perfectly, and helped us find some decent restaurants while we were there. The fact that your journey ends with streetview pictures of your location is just icing on the cake.
On the way back to the airport I was complaining that the stock voice is pretty horrid, and wished there were replacement voices. Apparently, I’m just an idiot, because there are. For $3 per, you can get a whole bunch of voices for different languages from SVOX. They’ve got an application that lets you hear a sample of all of them, and after poking with that for a few minutes I bought the Grace voice.
The voice engine is deeply integrated in the Google stack, so you basically just change the default voice engine in preferences, and from there on out everything that speaks to you, does so with the new voice. The only exception I found was Tasker, so I needed to specify which engine to use for it to read me incoming text messages when the headphones are plugged in (which is likely when I’m driving in the car.)