If you're not familiar with the website Teen Reads, then I would highly recommend becoming familiar with it. It has some really fantastic features on it. These features include new releases, lists like historical fiction or adult books about teens, and a great list of what books are being made into movies. They also run seasonal giveaways that include tons of popular books.
If that's not enough to win you over, or you prefer your book sites just to be lists of books, then I would tell you to have a look at their ULTIMATE TEEN READING LIST. This book list is my personal challenge. It has over 400 books on it and I love looking through and counting how many I've read. And it's a cool way to stumble upon new titles.