The iPad will fail.
The iPad will succeed.
Actually nobody knows.
Fact: there are now tons of analysts speculating on MacRumors.
It just amazes me how so many people care. It is a tool. Some tools work better for one person, and not so well for another. It comes down to personal preference and need.
It does have some casual computing potential. For me it will lighten my load (textbooks + MBP), take notes, work as a sketchpad, and help keep me organized. I can browse the web (I don't play flash games (app store) or watch porn, so I don't mind flash missing--I use clicktoflash anyway), and write emails on it between class. In the evenings it will be a great coffee table computer (or picture frame - beautiful IPS display) that my wife and I can share, as she isn't allowed to use her work PC for personal use and her personal Dell recently crapped out. I also imagine it will be more comfortable for us to curl up in bed and watch a movie on than a burning hot MBP.
It won't replace my MBP for my graphic design work and photo editing, but I don't need to lug that to class either. Both are tools that have a purpose. Sure there is overlap in functionality, but they both have their strong and weak points and both have a place among my personal toolset. Just because a tool is useful for someone else and isn't for you doesn't give you the right to knock it or attack them personally (which has happened in many threads I've read). I don't really care if people think it's terrible, but I'm not going to try to make a mockery out of you. It just isn't something that is useful for you. Not a big deal. It isn't a perfect machine, but what is?
As for whether or not it will succeed, lets chat next year? Also remember: don't count out OS 4.0 and beyond.