Never mind the fact that most current media players can also do video and games, and sometimes even browse the web (iPod, Zune), a Kindle or Nook can play music (although the Kindle clearly has far less memory available), and the Netbook can do all the functions mentioned (although it may not be as snappy or small a package)...but you had to go and throw a 9" screen DVD player in there too? Really??
I don't recall reading that the magical iPad plays DVDs as in the insertable media - obviously it can display video. (oh, but some netbooks do have slim drives). If you're just throwing that in for the equivalent screen (again, netbook's already got one), then why not add the price of an eInk screen to the iPad side of your equation, as your pile of dedicated devices offers eInk or LCD displays in various sizes (and resulting battery lifetimes) while the iPad doesn't.
Sorry, but that's one of the least convincing "comparison" methods I've ever seen. I'm sure the iPad will sell just fine without that kind of help. (And no, not to me, but I'm not just being a hater.)
I'm not sure why people expect or demand that this device or any other be 'magical' or a device that replace all others. There are still other phones out there besides the iPhone, and there will be other devices out there like the iPad, that people will choose depending on their needs, budget etc.
I don't think this device will replace my laptop (for now) but it certainly could in some situations, particularly if Apple allow certain things to happen like attaching a hard drive. Apple's changes to the file management system certainly open possibilities for image database management which is my main interest at the moment. But having a device that potentially can perform all these functions, including more esoteric ones like a remote control are intriguing. I think this pad would make an awesome GPS screen appropriately mounted in the car for example - I use Google Maps routinely on my iPhone in the car - even that app will be awesome on a larger screen.
I think it all depends on the apps that develop and to what degree Apple 'unlocks' the device to add accessories etc for alternative uses. No reason why a camera could not be plugged into this device for example, from a small video camera to a tethered DSLR, USB hubs etc.