Applications I recommend for the iPhone

GAMES/FUN

• FieldRunners - Tower Defense
• Zen Bound - It really is somewhat Zen
• Trism - Sliding puzzle game using accelerometer
• SET - based on the puzzle card game
• Quordy - Like Boggle with multiplayer challenges (challenge me at kc at kevnull)
• Galcon - Simple but fun galactic conquest
• KERN - Your score = (font  size / leading) - kern. Need I say more?
• Lightsaber - because you can swing it around and make lightsaber sounds

MUSIC

• Last.Fm - to scrobble and for the radio
• Remote - control iTunes. I use this all the time.
• RjDJ - coolest dynamic music app. Uses your surroundings (need iPhone headphones)
• Shazam - Music recognition
• Ocarina by Smule - one of the coolest musical instrument apps
• GuitarToolkit - very full featured toolkit including chord progressions and tuner

NETWORKING / COMMUNICATION

• Tweetie - multi-acccount Twitter app with saved searches. My preference.
• TwitterFon - for a free Twitter app that does the job
• Fring - IM/Skype
• FourSquare - Location app to show where you are and where friends are
• Favorites - nicer view of favorite contacts you call/sms/email a lot
• VNC - for when I really need to control my computer from my phone

MEDIA

• AirMe - Instant uploading of photos to Flickr, Photobucket, etc after you take them
• Radar - integrates with Flickr for a nice interface to Flickr photos
• CameraBag - awesome effects for photos taken
• SnapTell - take a photo of a book/game/dvd and it recognizes it for you

UTILITIES

• Things - used with Things.app for todo / GTD system
• Evernote - take photo, typed or recorded notes and sync with desktop app
• InstaPaper - bookmark online articles to read on phone later
• Units - Free unit conversion
• Dual Level - leveler
• Translator - lanauge translation
• Stage Hand - Remove Keynote control (if you don't have iWork '09)

LOOKUP

• Yelp - location based local restaurants/stores
• Taxi - taxi providers in your area with phone numbers
• Wikipanion - looks up wikipedia in a nicer ui
• WeDict - dictionary
• Now Playing - movie times with Rotten Tomatoes and Netflix support