Eclipse. The third book in the series. Personally my favorite, since it has the most action. It's not lacking romance though, which also helps with it being my favorite. Anyways, in this book, Edward and Bella are back together. The three, Jacob, Edward, and Bella are in a love triangle, revolving around Bella. A fight gets happening later on.. but I wont say as it'll give away the book.
I would recommend this book everyone, as always. Has tons of action, suspense, romance, and so on. I've read it 5 times, and I am currently reading the series over again, so it's soon to be 6 times. Very, very, awesome book.