I've seen the newest Tom Tom navigation couple of days ago and there was one feature that came in very handy.
The bar at the very right side of the navigation that showed some of the POIs - e.g. Petrol station, Parking that are along side of route and it also showed how far you are from these POIs. I think this is very helpful when driving on the interstate or in the area that is completely unknown to you (for example knowing that the Petrol station is 15 km ahead of you can really help)
I understand that this may not be easy to implement but as I said, this feature was very helpful