Glypish Pro 3
400 icons, in both regular and retina-display sizes, for $25. If you're an iOS developer who cares about the quality of your app and you don't have this set of icons, shame on you.
iPhone 4S and iOS 5
The 4S is a nice, comprehensive update to the iPhone 4, but the real magic, to borrow a phrase, is in the software. I've been using iOS 5 for months now, and despite having to deal with some incredibly annoying bugs and a raft of broken apps, never once considered downgrading to iOS 4.