I have been reading ebooks for about 5 years now. Mostly I buy them from Fictionwise.com and most often I download their sci-fi short-story Nebula-award nominees series, which they publish once a year, for free. But, I’ve probably spent on the order of $200 on other books as well.
Oh, and I subscribe to Scientific American digital (monthly) and read it as a PDF on the screen rather than get all that paper that just piles up before I can get to it.
As in quantum-tunneling effects, you can get me past the initial resistance to an ebook if:
- The price of the ebook is 60% or less than the price of the physical book; or if
- I don’t want the physical book hanging around anyway after I’ve read it; or if
- It’s available in PDF so I can read it anywhere (though I do purchase prioprietary DRM formats frequently); or if
- It’s $9.99 even if I think I could find a paperback for slightly less somewhere else.
It is just so much easier to take an ebook with me and read it on my screen (or iPhone in the case of the Kindle and Fictionwise readers)!
 I use quantum-tunneling as a metaphor all the time. Read about quantum-tunneling here in Wikipedia where it’s a difficult article to follow, but go the the paragraph that describes Shroedinger and has the little illustration of the “tunneling” particle (see above).
 There’s a Kindle book reader iPhone app that allows you to buy and download Kindle books from Amazon to read them on your iPhone. No reason this wouldn’t also work on the iPad, since they say 140,000 apps already run on it. (I wonder who took the time to test that assumption…) Fictionwise.com also has a reader available in the app store.