I just finished reading the Fifty Shades Series by E.L. James and it seriously is Twilight without the supernatural and written for an older age group. I liked the first book more than the other two but they were all really good. I read online that it started out being an erotic story based on Twilight and that it is. Anastasia (Ana) is Isabella (Bella), Christian is Edward, and Jose is Jacob and all the other characters fall into place. Christian is an older unsocial wealthy guy interested in younger virgin Ana. He warns her to stay away and how dangerous he is and she just doesn’t care. Her parents are divorced, he was adopted, he has the over enthused sister and tough brother, her dad is best friends with Jose’s dad, etc… 

I really liked the stories. Except for the parallels with Twilight the books are unique and definitely keep you wanting to read more and more. I would definitely recommend them to anyone that likes adult stories or romance or just wants to try something new.