1-Twilight
2-New Moon
3-Eclipse
4-Breaking Dawn
Twilight will always be my favorite out of the series. It has the best lines, and it focuses on Edward and Bella's relationship the most, IMO.
New Moon's my second, because their reunion at the end is so cute. And I believe that the things that happen only emphasize how deeply they care about each other.
I like Eclipse, but I feel like it was kind of uneventful. I mean, yeah, Bella finally chooses Edward. Jake is all teen angsty and runs away. And they defeat the vampire army. But that's basically it. It felt kind of like the POTC 2 for the Twilight saga. xD
Breaking Dawn was just weird. I mean, a half-vampire, half-human baby? Really? And I felt like there was really no focus on Edward and Bella, which is what the series is ultimately about, and what got me hooked on it in the first place.