I'm a big interlibrary loan fan too - especially when it can be done completely online. I just search the county catalog for my book, pick the library I want it sent to - and get an email when it arrives. My library's not that big, but the county network is, so I can get just about anything I want. Proved very handy in grad school, too - I got stuck with a book for a paper that wasn't located ANYWHERE in the area - would've had to buy it, but one of the other UW campuses had it, and let me have it for the entire semester.
I find it hard to convince myself to spend money on books, especially when I think about how many boxes of them I gave to our last rummage sale, and how many are still in my basement, unread.
I didn't really use the library for leisure (as an adult) until I started library school, maybe 4-5 years ago. It's easy to forget about it, if you don't visit often.