Apple already proved with the Ipod/itunes combination that consumers are willing to pay for music even though the recording industry said they weren't. The same is probably true of print - it's simply a question of delivering a great user experience, no hassles, and low transaction costs.
Absolutely. Looking at the video in the above link, it appears they will nail "great user experience" (obviously I won't know for sure until the iPad is in my hands, but those Space, Human Body and Travel app/books look slick).
Apple seems to have the "no hassles"/"low transaction costs" angle covered for the consumer.
I think premium magazines are going to make a huge comeback on the iPad, with a lot of attention paid to rich media, professional design, and smooth transition effects (none of which the Kindle has).