Last week, I was waiting for a friend of mine and, while waiting, was reading on my nook eReader. He hadn't seen it before and after making appropriate noises about the case (which I made) asked me whether I saved money by having one. Not at all, I had to tell him. I may pay a little less per book for new books, but I more than made up for it by buying so many more new books. I still love used books sales, and I prefer to have nice hard cover copies of my well-loved novels, but for day to day reading, ebooks had really spoiled me.
I'll give you an example. Yesterday morning, I woke up very early (one of the hazards of being pregnant, I've found, is how hard it can be to sleep in). I had just finished one book and, as is so often the case, was uninterested in the TBR pile next to my bed, or any of the other books on our shelves I've never read. So I picked up my nook and looked at the Wishlist I had created there. One title stuck out at me - The Magicians by Lev Grossman - so I bought it. A few minutes later I was happily curled up in my comfy chair reading it. All this, before the sun had even come up all the way.
I still love physical books and I can't ever imagine not being surrounded by them. But I have unabashedly become a fan of ebooks, and I foresee that as time goes on, I will buy even more of them.