I know it's a children's book series but I would have to say Goosebumps by R.L. Stine. I was around 7 or 8 when I first read the books and these books helped me love reading! Once in a while I would read back the older books in the series and I just love the nostalgia and realizing how many books I've read and adventures I've been on because of Goosebumps. Sorry it's a bit dramatic.
