Please note that if you jailbreak any iOS devices (iPhone, iPod Touch, iPad), the warranty will be null and void. Apple will refuse to repair any iOS device that has been jailbroken. Additionally, do this at your own risk, as jailbreaking will expose you to malware, which targets jailbroken devices. If something does go wrong during the jailbreaking process, Apple will refuse the repair it. Jailbreaking is considered tampering, and as such, the warranty will be void. Just keep these in mind if you want to attempt this risky procedure.
If you have the latest version of iTunes, you can now re-download what you purchased!! This works for any music files you've purchased in the past, as well as television episodes and Apps. Movies will take some time for Apple to negotiate. It's part of iTunes in the Cloud. I find this very helpful in the event I lose my music files. However, a lesson is to be learned here: Back up your iTunes files regularly. What you need to do is to locate the iTunes folder and copy it onto a storage drive. By doing this you can preserve even your settings and playlists you've created. For Mac users, you can use Time Machine, which backs everything up.