The ipad can do word and powerpoint. All i really need for collage.
Even though this might seem to be the case now, I think that colleges are moving towards using laptops for more purposes (ie exams) all the time. The only reason I say this is because you should probably be over-inclusive in your estimation of what you might need in a laptop/iPad rather than under-inclusive.
But to respond to your main question: I think that the iPad is amazing because of its size, ease of use, intuitive apps, fun apps, and wide breadth of possibility. As you said, you would be able to get all of the word processing and powerpoint apps that you might need, and if you needed to type something really long, then you could just get a bluetooth keyboard. So those are points in favor of the iPad.
My main concerns, though, are the size and durability of the iPad and compatibility issues. While I think the screen is perfect for home and recreational use, I would be frustrated if I had to look at my notes on such a small screen all of the time. But this could just be personal preference, since I need to look at outlines to study. I guess I'm a "big picture" kind of person. I would also be worried about dropping or scratching the iPad. College life is hard on even the sturdiest of laptops, so I can't imagine what it would do to an iPad-what with the drinking, partying, dancing, etc. that occurs on a college campus. My other concern would be that there is not a stand that holds the iPad up at eye level so that you don't strain your neck looking down at it all of the time. I find that, even with my medium sized laptop screen, I tend to get a lot of neck and back pain due to looking down at the screen all of the time. But there is no way of knowing if there will be a suitable stand for the screen by the time you make it to college. Overall, I would say just stick with a laptop. You know for sure that it will do what you need, and you don't risk compatibility issues. Best of luck!