Twilight of course has a special place in my heart, but I'd say Eclipse.
To me, everything I was waiting for happens.
Edward and Bella decide to get married, they decide she will be a vampire, and most importantly Edward conquers his bloodlust. To me the most significant moment in the series is when he bandages up Bella's hand and can breathe in the presence of her blood. We suspect he's getting over it, but at that moment we are sure he will never hurt her. And most importantly, Edward is sure he will never hurt her.
Also, there are lots of sweet moments. My favorite cheesy line that is on my signature is in Eclipse.
Plus there is all the emotional stuff with Jacob. Sometimes I want to kill Bella, but lots of it makes for great reading.
Oh, yeah, I love the tent part and the action stuff is awesome, and I don't even like action stuff.