The thought of Batman dying in a film turns my stomach, quite frankly. If it is done, it better be done really, really well because that is a move that takes some balls. On Nolan's part, I guess it would be pretty smart, as it would bring his series to a definitive end, so noone else could come along and tamper with his world. On WB's part, it seems like it could make quite a mess out of things. They don't want to reboot again and so soon, do they? I always figured that we'd be seeing a new director after TDKR and as a result, would get a bit of a different vision, but I at least thought that the Nolan trilogy would serve as the building blocks of that. If Batman dies, that's not possible.
I don't know why, but I just get the feeling that the death of Batman is a very real possibility in the Nolan series. I feel silly saying that and I'll feel even sillier if and when it doesn't happen, but considering the rules of the world Nolan has created and scale of the story he is trying to tell, I just can't say for sure that it won't happen. In any past films, you just knew for sure Batman couldn't possibly die. With this film, that possibility feels pretty real.