3. Walt Jr.
Could Walt Jr. be set for a tragic end come the season 5 finale? The flash forwards would seem to support this theory considering none of them show Walt with his family, indicating that they're no longer of the living. We know that Walt has an M60 machine gun and ammunition in the trunk of his car and he looks pretty geed up for vengeance - it could be that the death of his only son was the tipping-point for his final stand. Nothing could hurt Walt more than the death of his son or wife Skyler, and it would be a tragic, heartbreaking way to end the show's run. With Heisenberg already on the ropes following Hank's discovery of his second life, the death of Walt Jr, probably after being caught in the crossfire, could be the catalyst for the show's final few episodes.