You know, the article I linked to below shows kids reading two books that are old, but which I would gladly take off their hands if they were going to throw them out... It's true that a lot of books of that vintage are suspect (and probably in bad condition), but then again, most of the Dr. Seuss books are older than us. :) That's fiction, mind you. A lot of that can be repurchased. Non-fiction gets stale really fast (overnight, sometimes, in the case of history and social studies).

It's good that you're able to make a fresh start with the guided reading stuff -- I wouldn't be surprised if they were still using the same reading comprehension sets I used at my junior high!