Duncan Wilcox on Twitter:

iPhone hardware might be exciting but once you turn it on it’s the software that sets it apart from other smartphones. Focus is iOS 5. Thinking about tomorrow’s announcements if you hadn’t guessed.

He’s right, of course. What sets Apple apart is the OS, rather than the hardware. People bang on about the lack of ports, extensibility and other features of iPhones, which some competing devices have, but Apple’s sleek and simple iPhone 4 remains the USA’s number-one smartphone for a reason: what you can do with it.

Tomorrow will almost certainly see iOS 5 released. This will bring some catch-up features like notifications that don’t suck, but also iMessage (unlimited, free text messages to iOS 5 users), Newsstand (iBooks for magazines), and PC Free (back-ups to iCloud and over-the-air updates). In addition, iPad 2 owners will get AirPlay mirroring of everything on screen to an Apple TV.

I’m sure there will be new hardware, but I don’t really care what it is, as long as it looks nice enough and isn’t any worse than the iPhone 4. And I’m certain that I’ll buy a new iPhone, but that’s only because I never grabbed an iPhone 4 and have been patiently waiting for an upgrade.

I suspect that regardless of what Apple reveals tomorrow, disappointment will speed across the internet like a virulent disease (which, naturally, will particularly affect tech hacks and analysts, who’ll yell that, yes, Apple is finally doomed! Again!), and if Apple’s new hardware really is only going to be the iPhone 4S—a minor update—it’s a pity that’ll be Tim Cook’s first keynote. But even if that is the case (and it might not be), it won’t distract me from what matters: the software. The phrase I’m most hoping for tomorrow isn’t “and here’s the new iPhone 5”, but “and iOS 5 is available for download today“.