Cory Doctorow has a great article on BoingBoing about what's wrong with the iPad, philosophically rather than technically. I'm very sympathetic to his viewpoint, but it ignores some crucial points.
The iPad will not replace personal computers, locking the world into a Jobs-controlled nightmare. The hardware tweaking culture is as healthy as its ever been - see the www.hardocp.com&geo=all&date=all&sort=0" target="_blank">traffic stats for sites like OCAU and Hard|OCP. And the plethora of online information combined with modern languages make learning software development much easier than in the past. In many ways it has never been a better time to be a hardware or software geek.
Rather than replace PCs, the iPad will increase tech literacy. The target market is not the traditional PC user, but the same market that Google's ChromeOS is going after: people who currently don't use computers. There's a secondary market of gadget geeks and fanboys (Apple and Google) who will also get on board, but they will use it as a second device. And while new users might stick with the AppStore apps for a while, eventually they'll get into this Big Bad Internet thing. That is, the tech market will expand, and with it so will the opportunity to get into tech geekery.
The AppStore walled garden environment is an issue, but a temporary one. It frustrates me no end that I can't write iPhone apps without a Mac, and that even if I could the app would have to pass through a gauntlet before it could see the light of day. But all that does is force me towards a more open platform - the open platform - the web. As on any device, web apps are limited compared to native apps, but that is slowly changing. Offline capability and native rich media support in HTML5 will mean that web apps can take a huge step towards their native counterparts.
So the app argument is a temporary distraction. On the PC there's been a significant move towards the cloud in the last couple of years: why do people think the mobile/tablet scene will be any different? With their lower specs and constant wireless connectivity, these devices are perfect for cloud-based apps. While the platforms are maturing apps will be important, but that importance will shrink over time. Every device, particularly the lower end ones like phones, netbooks and tablets, will primarily be a window to the web. Google understands this. Microsoft understands this. Adobe understands this. Maybe Apple does, maybe they don't: it doesn't really matter. All that matters is that every device has a modern standards compliant web browser.