Some authors don't do character deaths. For me, I want people to be happy when they finish one of my books, so I tend to avoid killing a character that my readers love (unless I'm planning to give them a new role post-death).
My fiance, Jim Butcher, takes a different view. He says that character deaths are powerful storytelling tools because if no one ever dies, then the danger never feels real to the reader because they know everything is going to be all right. He says readers want to be invested, they want to feel BIG EMOTIONS, and part of that is making sure the stakes are real.
So tell me what you think.