Cobb Is Awake
The Wobble: If you look closely at the final shot, the spinning top begins to wobble and lose balance, indicating friction and gravity are acting on it rather than spinning forever like it would in a dream
The Wedding Ring:
Cobb's true totem is not the spinning top (which belonged to his wife Mal), but his wedding ring. He wears his ring during dream sequences, but he is not wearing it in the final airport and home scenes
Actor Michael Caine stated that director Christopher Nolan told him any scene featuring Caine's character (Professor Miles) takes place in reality. Caine is present greeting Cobb at the final airport scene
