I read a fic that had Sam and Dean in the future--Dean in his late forties, I think, or somewhere around there, heading home to take care of Sam, who has a really bad cold. It was sweet and realistic, with them being the teachers of the next generation of hunters, and settled into a reasonably stable life. And it was so nicely done that I could see something like that being a viable alternative to going out in a blaze of glory.

I think that's why even if no one else reads my AU I'll still keep working on it, because so much of my own feelings get worked through along the way, and I can express things that I can't any other way. But I love AUs because exploring other interpretations, other forms, or perspectives is such a valuable and rewarding exercise for any writer.