With the announcement of some new features in Apple's iPhone OS 4 yesterday, I have to say, it will be nice to be able to leave the Pandora app but have its music still playing. The big thing for me though is Apple's new restriction on programming languages. They've essentially made it impossible for Adobe or Microsoft to make software that can compile applications as iPhone apps. I understand Apple's business motives (John Gruber has a good summary up on the topic), but it just doesn't sit right with me. Between the app store and this programming language restriction, Apple has the iPhone entirely locked into their proprietary development ecosystem, as I'm sure they want. However, I saw some speculation that Apple is actually trying to damage Adobe so they can acquire them down the road. I'm not saying it's plausible, but they certainly have ability to do it.
For the most part I'm mad simply because I was looking forward to making iPhone apps with Flash CS5. I have years of Flash and ActionScript experience, but haven't touched anything resembling Objective C since undergrad. With the looks of it, I will have to suck it up and learn how to build apps the Apple way after all if I ever want to make one of my own.