I have a Droid Incredible phone I've had for a few years.
I'm not too big on phones in-and-of-themselves (seriously people, if you identify with your freaking phone you're a loser) but it is useful to be able to take high quality photos of musical compositions I'm working on and email them to myself, to make low quality audio recordings of ideas I have when I'm too tired/lazy to notate the ideas, and …
… to not get lost.
Google Navigation is pretty helpful. What I usually do is email myself directions, then when I get in my car I click on the address I'm headed to and just follow the voice telling me where to go.
The problem is that at some point clicking on the message body's link on my phone (circled in red in the image below) stopped launching Navigator and would just launch Google Maps in my browser, meaning I've had to type/paste the address in the Navigator bar before I could get voice directions. My guess is that some update caused this to stop working.
But it seems like if I click on the street address in the email subject line itself (yellow highlighted in the image below), the actual Maps app launches from where it's easy to click on the Navigation icon and start hearing the directions.