One of the things I like to use my iPod Touch for is reading the Bible. There are many apps to choose from with different features. The ones that I use are BibleReader and Accordance. Both of these are offline reading apps. BibleReader is available on a variety of mobile devices and has some excellent features, particularly the navigation to allow quick access to any verse. BibleReader 5 added significant enhancements to give it further capabilities for Bible study. The Accordance iOS app is fairly new and allows access to modules from the Mac program and its powerful search capabilities.
BibleReader iTunes link
Accordance iTunes link
One of the other Bible apps is the YouVersion Bible app allows for both online and offline reading. Right now until March 1, along with Biblica, they are offering the NIV translation free for offline reading on iOS and Android devices.
Youversion iTunes link