These apps have worked their way into my life and are worth checking out.
Everyday or frequently:
Safari, Tweetie 2, Now Playing, Amazon.com, YoContacts, iTalk, IMDB, Squarespace, Analytics, Tumblr, Mint, Kindle, Google, RedLaser, AroundMe, Files, Labyrinth 2, Dragon's Lair, TheDeep, Kayak, Zenbe, Facebook, Todo
Sometimes but good:
1Password, BeejiveIM, Darkroom, Driver, Flickr, GPS Drive, GoodReader, Google Earth, Gowalla, Instapaper, Lose It!, Matches, NOVA, OpenTable, PAC-MAN, Pandora, Postman, Pzizz Relax, Remote, Rotton Tomatoes, Shazam, Skype, Taxi Magic, Trails, TripIt, Yelp, Zipcar, iTimeLapse, iWant