Don't neglect the "old" books, those that you may not find in Barnes & Noble. I could spend hours listing some of the authors I grew up reading in the fly fishing arena.
Stop in any and all used books stores you see. 99% of my collection came from those places. And while you're at it, take a ride up Route 209 and head to Route 54 and the Hometown Flea Market on Wednesdays, lots of books floating around there.