Angry Birds is a fun time waster
Words with Friends (scrabble with friends or strangers. I often kick Bill Duty's ass at this game
)
Card Star (get rid of the key ring barcode cards for stores & enter them all in one place)
Red Laser (scan a product at a store & you'll see if there's a better price at another store)
Unblock Me (game)
Around Me (great for traveling. It picks up your location & gives you a list of local restaurants, stores, ATM machines, shows, etc)
What to expect when you're expecting (LOL, well, maybe not that one for you)
TV.com App (can watch your favorite TV shows)
Shazam
Word Warp (game)
Open Table
Dragon Dictation (you can speak into your phone & it converts your words into text instead of having to type it all out)