So, who does the iPad work for as a PC replacement? Most people, really. My father, my in-laws, my brother, my best friend, my cousins, my neighbors. People who are still using a Windows XP PC. People who think that Google is the Internet because it's the home page when they open their browser. People who think they can't switch ISPs or they'll have to get a whole new Hotmail account and start over. People who buy a PC from Best Buy and basically use it as is out of the box.
The reality is that the iPad--particularly the iPad 2--is not only capable of handling the computing needs of an average user; it is probably a better choice than a PC. It is easier. It just works.
You can give an iPad to your Luddite grandmother who has never used a computer and she can surf the Web and send an email in a matter of minutes. You can give an iPad to a three year old, and they can intuitively navigate the interface and use it without a second thought.
The iPad can do these things, and it's more versatile than a desktop PC--or even a notebook or netbook--because of its form factor. You can read a Kindle book on your iPad in bed, stream a movie from your iPad to your 42" LCD TV in your living room, video chat with your parents from the den, and cook dinner using a recipe from the AllRecipes app in the kitchen.
The iPad lets you check your email when you have a spare 30 seconds standing in line at the bank, or post a status update to Facebook about the guy next to you on the train with two different colored socks. The iPad lets you read National Geographic, keep up with breaking news on CNN, or watch your favorite HBO series while sitting in the waiting room at the dentist.
Can you do these things with a notebook or netbook? Sure. Can your grandmother or your three year old do them intuitively? Probably not. Would you want to get out a notebook PC, open it, boot (or wake) it up, and try to hold it in one hand while navigating the touchpad with the other just so you can check your email while standing in line? I doubt it.
I don't plan to get rid of my notebook. I don't recommend that any of my techie friends dump their PC any time soon. But, for the vast majority of my friends and relatives, I have no reservations whatsoever telling them that the iPad is all they need.