The Sopranos has defied expectations since its inception almost ten years ago, so my method for predicting what's to come hinges on the following:
Step 1. Predict the obvious.
Step 2. Invert the obvious.
Obvious: A.J., heartbroken and brooding over the evil of man, kills himself.
Inversion: A.J. kills Tony! Perhaps his depression causes him to dwell on the ugly brutality of his world, and when he discovers one of Tony's evil deeds (killing Chris, killing Adriana, etc.) he takes it upon himself to rid the world of his father's violence.
That would be rad.