Zite Essential app for staying up to date with any kind of daily news. The most flexible and customizable app out there, bar none.
Pocket (Formerly Read It Later) Whether reading a page in Safari, or browsing news in Zite, Pulse, or Flipboard, you'll want to sign up with Free App Pocket so you can save your articles and pages for off-line reading, at (get this), NO COST.
Waze social GPS, maps & traffic Totally FREE GPS and turn-by-turn navigation. Not as accurate as Motion GPX or TomTom, but it does have a unique cachet in that it informs you of accidents and other activity on the roads in your area. Essential first time download for all drivers.
GasBuddy - Find Cheap Gas Prices I paired this app with Waze when I first got my iPhone, and it has saved me plenty in gas dollars, allowing me to cut costs constantly whenever I travel. Nothing beats the convenience of just glancing at your phone and seeing whether or not the gas down the road is cheaper than gas at your workplace or in other areas of the city.
GroupMe™ Essential free-text and group conversation app, this will soon replace iMessages with its flexibility and ease-of-use.