JJ is right. If you want to unlock the phone to use on other carriers, then you need the oldest firmware you can get. If you are going to be using AT&T and don't mind it being locked to that network, then leave it be and update at will. Jailbreaking is nice for extra apps, but 1.1.3 probably won't be completely jailbroken until after the SDK is released next month. There will be some good apps coming down the pike that you'll be able to purchase through iTunes just like you purchase games for your iPod.