The magic that I hope ties them all together well is iCloud. I'm a content MobileMe user right now. I probably don't lean on the service as much as I could but it works for me.
iCloud, to my eyes, represents that next leap forward. I sold my first generation iPad a few months ago and I miss it. What I don't miss, however, is the management of non Universal apps in the app store. I remember thinking that if MobileMe could sync an app then the Universal version would be ideal because then it "connects" my iPhone with the iPad and makes for or more powerful system. A las MobileMe was not up to the task but it appears that iCloud is and here are my hopes for iCloud.
1. Pervasive support. If an app is available on the app store and that app deals with data or documents that can be sent. I want iCloud.
2. I want developers to skew towards Universal apps even if the pricing needs to be higher rather than deliver separate iPhone and iPad apps.
3. When possible I'd like to see a Mac app even if it's basic. At times I don't need a full fledged Mac app but rather something that's going to let me get data in or read data later on a larger screen. I'm starting to prune task apps that are iPhone/iPad only. Mobile devices are great but they become even greater with Web/Desktop OS access.
Lion and iOS 5 are big big big. I'm sure developers are going to ante up on iCloud and other stuff but I hope they leverage these tools and realize that it's ok to ask for money. The only way someone can show you they care about your product is to pay a fair price.