1. Stephen King
I've said it before, and I'll say it again, SK was popular by the time I cut my reading and writing teeth, though I didn't touch one of his books until I was a senior in high school. The first book I read by him, The Eyes of the Dragon, was freaking awesome. I was brave enough to try some of his other books, Firestarter and 'Salem's Lot. I liked them. As far as fame goes, I think he deserves it. He can tell a good story.
I've said it before. Twilight is popular for 2 reasons: 1 - it's easy to read. 2 - There's hot guys. Millions of teenage girls who've never read anything else don't need a strong plot, a likeable heroine, or even an acceptable length. That being said, I did like the Twilight books, I just don't think they're the greatest thing I've ever read.
3. Harry Potter
My mom never let me read Harry Potter. It looks fun, though. As soon as I'm tucked happily away at the W, I do plan on reading them and watching the movies.