At 16 I got way, way too entranced by Ayn Rand and Atlas Shrugged. Good news, it prompted me to go get my philosophy degree and realize that while she is a fantastic fiction writer, her ideas have some rather large holes in them. Bad news, I think I alienated all my high school and early college friends. I still read Atlas Shrugged every few years though, just to test my resolve and enjoy the story.
The Lord of the Rings has never lost any interest for me. I loved it when I was young, but I think more for the fantasy elements and now I love it for the great characterization and the complex back stories. I can never wait to get to the end of Return of the King and read the appendices.
I think that I grew into contemporary fiction. I used to refuse to read anything written after 1950 - it just didn't have the sense of historical perspective and timeless nostalgia that I thought I read books for. But, I just read my first Murakami book, Kafka on the Shore, and was completely mesmerized by it. My boyfriend also knows Don DeLillo and is a great fan of his works, so I guess I should pick that up soon too.
The other thing I have grown into, or maybe just was never exposed to when I was younger is comic books/graphic novels (again, boyfriend inspired). He has almost all the Tin Tin comics which I am reading between novels and for some reason, I just love them. Star Wars, Batman and Sin City graphic novels have been a great find as well.