Well, I live a solid 20 - 25 minutes from a library
So I went digital about 7 years ago - gutted it out on pocket pc devices for all that time. Have bought about 280 books - half of them being drm'ed. And, I love, love, love not having to hike to library every two weeks, carrying a load about 20 books in since there's not nearby parking, waiting in line to check out, and never being able to get new books because that entails reserving them and then picking them up w/in 3 days of coming in - I simply can't make it to the library that quickly.
W/ the Sony PRS 505 - I have been blowing through some books - I am able to read much faster than on my pocket pc devices. I have been able to get back my entire collection (since I bought my last phone that was incompatible w/ Microsoft Reader). And, I am a happy camper.
I do trek now for my daughter - she has the same bad habit - 20 books every 2 weeks (more if I could stand to lug them back and forth)- and our library system is very small so the young people's book selection is quite limited and she's read everything appropriate on the classics / Gutenburg site. And, since it's not her money - I won't buy her digital books :-)
I'm going to have to purchase a library card for the next county over once she finishes all the books in our system.