Oh, so many reasons, but I'll try to sum it up. Jailbreaking allocates the user a level of access that Apple would NEVER give you. I love the assortment of Addons that are made availible in Cydia, as well as the ability to change your theme and even the layout of your springboard. It also gives you more options as for what you do on preset Apple applications. I have Safari Download Manager and iMobile Cinema, so I can watch videos on my iPod Touch and download them, and watch them later using iFile. I didn't cover all the reasons I jailbroke, but it's the things I really wanted to state.