So I just finished a book last night called "The Host" by Stephanie Meyers - it is her more adult Sci Fi book and I loved it. I highly recommend it - she really develops great characters. As with Twilight the ending to this book was a bit too perfect but that must just be her style. Overall a good read though. It certainly raises interesting points/questions about humanity...
(PS - For those non-Sci Fi readers out there the story line may seem a bit out there but it actually isn't too bad - it really ends up being about the characters so don't let it scare you away...)