It varies. Often I like the narations I read to start like the world is in danger, you can't let this book fall into the wrong hands, yadda yadda. For more actiony books, I like a prelude(sp) that tells a little bit about what the charactor is going to be facing, like in Eragon. For domesticated stories, I'm not sure what pulls me in. I think it's the tribulation the main charactor is going through. For example, her brother just died and she's trying to find a way to get over it.