For the vast majority of the books I read, I can check them out at my local library - which saves tons of money and space when I'm probably only ever going to read it once!
For most everything else, I get it all online. I read all of the blogs I enjoy through Google Reader, download podcasts on iTunes, and listen to audiobooks (I do enjoy reading, but sometimes it's quite nice to be read to - especially while I'm knitting, haha) via LibriVox and iTunes U (University of South Florida has a decent selection of books from the public domain - right now I'm listening to The Adventures of Huckleberry Finn by Mark Twain) - all for FREE.
As I get older, as the technology gets better, and as the prices go down, I can definitely see myself investing in either a Kindle, a Nook, or some other e-reader. For both the Kindle and the Nook, there is a lot in the public domain that can be downloaded and read for free - which is a big plus for me. But for right now, I'm sticking with my current method.
Edit: I actually just checked out four books today from the library: Writing Smart: Your Guide to Great Writing by Marcia Lerner, The Writer's Handbooks: A Guide to the Essentials of Good Writing by John Karls and Ronald Szymanski, Criticism & Ideology: A Study in Marxist Literary Theory by Terry Eagleton, and Brave New World by Aldous Huxley. Aside from the last book, none of these are books that I'd actually want to buy except for maybe the last two, and the last one, Brave New World, is in the public domain and can be accessed online for free.