Twilight
This is probably the most famous teen book released ... well, ever. I read it (and loved the cover art) but didn't find it as good as I expected. It took a while for Bella to discover what Edward was- but that info was on the blurb - half the story spoiled. I did, however, enjoy reading it to an extent.
New Moon
The part of the book I read (I didn't read it all), left me craving more! A lot more interesting then Twilight. I thought I was a die hard Twi-hater after the first book, but I really did enjoy this book. :) And am even going to see the movie.