I don't think anyone is arguing for the iPad as a replacement for a laptop. I still use my laptop- I just don't drag it with me to school everyday.
The iPad is a supplement, but that being said, I can imagine myself upgrading my iPad before I upgrade my laptop again (it is 2 years old). The laptop is great for writing and doing heavy computing. I still use it everyday. BUT- the iPad is an awesome thing to have in my bag with me 24/7, and at 1.5 pounds or less, it is not a big deal to cart around. Battery life is also superb, I use it for days before recharging.
Will I carry my laptop with me in the clinic all day? No, but I sure as heck will have my ipad in the inside pocket of my white coat. Some of the textbook options are great- I definitely recommend checking out the Ganong Physiology book which is not just a pdf, but made for the iPad, it's extraordinary. And I think there will be more to come. Not to mention First Aid, anatomy reference books, and about 5 other textbooks that I got free through my library that are now with me whenever I want.
Could I live exclusively with my iPad? I wouldn't, unless maybe I was traveling for a few weeks- but it certainly is an amazing accompaniment. The laptop stays home, the iPad comes with me.
Most people in college already have a laptop that will serve them just fine for word processing and making powerpoint slides. I'd say rather than get a brand new laptop for ned school, an iPad is worth thinking about.