I want to create an app, but don't really know what it should do.
I have 4 questions I would like to ask you
1. What is your favorite app?
2. What do you love about it? What features could you not live without?
3. What do you find most frustrating or annoying about it?
4. How would you recommend the app to a friend in one sentence?
My favorite Android app at the moment is "Commute" by MapQuest.
I like it because, unlike most map-oriented apps, like Google Maps, it is specifically targeted to letting you see traffic between two places you know the way between perfectly well--home and work. There is very little configuring to do (enter the two endpoints, basically). The part I cannot live without: where it tells me the hot spots are in traffic. Those allow me to divert to an alternate route. What's annoying--and this only rarely happens--sometimes it can lose track of where I am until I sit still for a while, or even not have input at all (that usually also is happening on Google Maps at that given time).
To recommend (advertise) it: if you just need to know how bad the road is between you and your destination, and you don't want to be distracted trying to enter crap while driving, get Commute.
As an aside, it is possible to just open this app (even while I have audio piping into my car stereo from Android), and just glance at it from time to time. I have a stick-on phone holder that lets me use the smart phone hands-free without having to buy a brand-new car.