Have I bought more books? Yes and No. To an extent I have bought more books, but in line with others I have been a hoarder (I still have paper books to read), and that Kindle Store is very tempting.
However, I have also learned to discipline myself a bit. Besides an initial infuse of books and a gathering of a lot of freebies (classics, promos, etc), I am learning to use a wishlist to control my spending, especially on books over $5. It isn't that I won't buy them, it's that I am forcing myself to read what I own before buying unless I am really in the mood or just need to read it right now.
Those darned $2.99 books, though, might just keep me from ever getting to that wish-list. I need to start adding them to the wish-list, too.
I do find I read more and faster with the Kindle. I'm not sure why, but with paper books, I found it was always making me sleepy, and reading was a bit of a chore, even when I liked the book. Now, I seem more energetic, and I look forward to reading.