To me (as a software developer), the most exciting thing about the iPad is the fact that it is integrated with the App Store. On the iPod and iPhone, the App store has proven to be a fantastic commercial success, opening a new distribution channel for software developers. There have been a few attempts to create similar type app stores for the desktop (or laptop), but none have been wildly successful. I think this is due to the culture. We are too used to downloading our software through the web browser - we don’t really see the need for an app store. If there was single app store for the desktop that allowed users to purchase /install software as easily as the iPhone app store does, I’m sure that the software industry would double or even triple in revenue in a short amount of time.
The iPad, being closely related to the iPod/iPhone in user interface makes it far more likely the at users will embrace its apps in the App store. This means that software developers who develop for the iPad will have an easy and automatic distribution channel for all of their works, where they can get paid in a simple and secure fashion. And the possibilities for application development on the iPad would appear to far exceed the possibilities of iPhone apps - nearing the level of desktop applications (or even beyond).
This simple fact is why developers will embrace the iPad. And when developers embrace a platform, historically, so too do users.