I won my choice of any iPad/iPhone app! What should I choose? What would you choose?

I won my choice of apps by fairly accurately guessing the configuration of the iPad2.

So I am totally beside myself trying to figure out what app I want.

Last month I already bought Navagon USA which I adore because it is a fully functioning GPS without a data plan or wifi so that one is out.

What is your dream app?
Why do you like it?
What is on your iDevice front page?