I generally beat every story in games I own (The exception being Fable 2, in that my dad stole my copy of the game while I moved out, the prick...) and I try to go for 100% completion unless it involves finding a gajillion different pickups that you have no way of finding without a walkthrough. Granted, there are some games where I will pick up a guide AFTER I've beaten the story and decide to play through again (Star Ocean: The Last Hope) to get all the goodies, and then there's Assassin's Creed 2, which I borrowed from a friend 3 days ago and haven't stopped playing except to sleep...