Originally Posted by
dtsm
What type of app do you seek?
I use [on both my 5s and new Moto G]:
waze for gps
yelp for food
tripadvisor for hotels
seatguru for flights/tracker/seats
Not sure there's a 'best' general travel app....this is what google says:
https://www.google.com/search?q=top+...en-US:official 
Agree on these...also...if you like to rent apartments rather than always stay in hotels, this app is useful and pretty:
Airbnb
Yelp is essential--I have discovered so many great places I would not otherwise have visited. My rule of thumb...don't go to anywhere 3.5 stars or less.
Finally, not everyone's cup of tea but I use and like Tripit