Make no mistake about it, the iPad is a wonderful desktop alternative for some. I know plenty of people who use it as their main computing device, which makes it live up to Apple's Post-PC billing.
But there's still one gripe in my mind that is holding the iPad back from true greatness. It's a missing feature that's inherently obvious when you're blogging, or doing anything else that calls for true multitasking.
The iPad needs a way to view two or more apps simultaneously.