Here is a short list of my favorite and most used iOS applications:
Although I’m not a huge fan of Microsoft’s operating system software, their search app has a very handy feature when you’re out shopping: Using the camera to scan a barcode, the app will find the product online, and do price comparisons.
Chase
Besides being able to check your balances and whatnot, the Chase app lets you deposit a check by photographing it with your camera.
Reeder
I can’t say enough good things about this app. It’s an RSS reader that connects to your Google Reader account, with a slick, elegant and intuitive interface.
This is a must-have for any guitar player. It features a tuner, a strum-able, and searchable chord library, and metronome.