Charging stations should be show in the Nav system. When setting a destination, they should be shown along the route. A “energy planning” screen could suggest charging stations and how long you would need to spend at them to make it to your destination or the next station. Using several different third party apps on my phone or on the browser in the car is inefficient and frustrating.
Other EV manufacturers have done (at least parts of) this.
Charging stations are now shown with v4.5 software. A tap at any charging station will navigate to that station.
I want to emphasize that an integrated planning tool is needed. It should work like this:
I plan a route from my current location to destination A. Now the navigation system should automatically calculate whether or not I will need a supercharger. It could do this factoring in my recent typical driving style as well as my current driving style. (e.g. average of 300wh/km). Now it would tell me for example: If you drive not faster than - say - 55mph you will not need a supercharger and get there at - say - 4:12 pm. However if you drive at - say 120 mph (I am arguing from a German perspective ;-) ) you'll need to stop at supercharger X for 20 minutes. Also you will have to take a different route to make sure that a supercharger is on the way. As a result you will reach point A at - say 4:38pm.
It should recalculate the route constantly according to the actual driving style en route.
AND: I would wish for a feature that lets me chose "fastest route" and/or a "making-sure-you-get-there-button". When chosen this feature would limit my max speed and/or max acceleration in order make sure that I will reach my destination in the fastest way. (driving slow might be faster, cause no Supercharger-stop needed) - or - simply reach my destination at all (in case of no Supercharger in convenient vicinity).
Am I making sense?
in short: I am planning to drive from Cologne/Germany to Nice/France. I need a navigation system that tells me the fastest way to do this in terms of route/supercharger stops as a function of driving style and then assists me by way of disciplining me to that driving style.
One of the more promising options may be Open Charge Map. You can (and should actually) contribute to that project to ensure that data is accurate, complete and up-to-date. They have a version of their website that is convenient to use on mobile devices, or in the Model S' built-in web browser: Open Charge Map Web App