It's not a phone, and it's not a computer. It's a new device class. Apple has made something interesting, and designed it well. It may catch on, but I don't like it myself. It's certainly more purposeful than a netbook, in that it knows what it's good at (browsing the internet, watching videos...) and doesn't try to pretend it's good at anything else (a netbook running a full desktop OS is wasting the OS's capabilities. Games, Photoshop, etc. are not going to work well on it so why not just stick with the basics?)
I've always liked the idea of the convertible tablet, and had wanted to see that catch on. That's less likely now, and I'm probably never going to see the market evolve to where I would like it anymore.
My absolute favorite rumored image of the Apple Tablet (which was incredibly and obviously fake) was this really cool looking device which looked like a big screen with a really wide hinge in the middle of it. Technically possible with OLED, and it had a normal laptop form factor allowing a "soft" keyboard to rest on your lap. I would like to see that product become reality.
Something else is that there were some fairly accurate mockups of the real iPad floating around the 'net the past few days, but the actual product has a disappointingly huge black bezel around the edges. Wasted space.