I have a number of iPhone apps now, and here are some of the ones I like the most:

• Pandora – Great for listening to Pandora music
• Google – Voice search is amazing.
• Pano – Takes panoramic photos.
• Rooms – IRC client
• FStream – internet radio
• Public Radio – internet radio
• Wikipanion – wikipedia
• Wordpress – Manage a Wordpress blog
• NYTimes – Read the Times
• iSSH – SSH client
• WiFinder – Wi-Fi stumbler
• Tris – Tetris clone
• Galcon – great arcade/strategy game
• Labyrinth – marble game
• iTalk – excellent recording app
• AquaForest – just plain fun physics sandbox