It's no secret that Federico Viticci is the master of iPad magic. He's done things in iOS that I can barely do with my Mac. In my opinion, he's one of the best writers on the web (and just an all around awesome guy).
He's released a new iBook on Editorial for iPad. If you are looking to move the majority of your writing to an iPad, then I'd highly recommend this book (and the app). It's the perfect way to go farther and faster with doing tasks that we previously thought were "laptop only".