Now, why I like Jacob? I can give some reasons.
First he is cute. How he cannot be? Or am I deluded by the image of Taylor Lautner?
He is hot. Literally. Due to the werewolf thing his temperature is so high that he does not need to wear so thick clothes, and sometimes no clothes at all... I would say somethings here but I am not a pervert so I shut up :)
He has humor. And perfect smile. White teeth :) I enjoy reading his parts because they are humorous and he uses sarcastic language. I loved 'book two' in Breaking Dawn which is written from Jacob's perspective.
He has confidence to compete with 'the most perfect guy' on the earth. The most perfect guy on the earth is Edward Cullen. But when you read Twilight, Midnight Sun and watch Twilight movie you are manipulated about all the good things about him. I liked Edward in the first place but till he leaves in New Moon and when Jacob comes into focus. It is also annoying that all the time Bella talks about how perfect he is, how nice he smells, how dazzling he is, blah blah blah... People get bored. Jacob loves Bella and even after Edward returns he continues to try hard to get Bella. I like his efforts.
He is loyal. He has never left. Well he tried to leave many times but always came back. He is loyal to his friendship even it hurts him so much.
He is strong, fast, big and hot. C'mon he is werewolf, what else can I say :)