The angle utilized right after Tony enters where we see him at the booth lends creedence to the audience-got-whacked theory. Also, Tony left the house and visited Uncle Junior in the state facility while on the way to Holsten's, and when he removes his leather jacket, he is wearing a different shirt in the diner. Somehow, I don't think this is a continuity error, but was done on purpose.
The Tony-gets-killed thing is also, on some level, a valid interpretation. As someone pointed out, it's the classic "the Lady or the Tiger?" ending.
The people in the diner were picked on purpose to screw with viewers, despite what Chase says.
The guy in the booth with the "USA" hat, is rumored to be the brother of the trucker that Christopher stole the DVDs from in Season 2. Other speculation concerns the man at the counter who uses the restroom, the boy scouts, and the two black guys at the display.
The guy at the counter who strides in just before A.J. could easily be a bodyguard, an FBI agent, or just a non-regular customer trying to locate the bathroom. Or just maybe he really is there to whack Tony, although to use the similar ruse to the one in
The Godfather seems a bit lame to me.
The Sopranos reference pop culture, to be sure, but usually it's not such a direct reference as all that. Besides, the angle that everyone keeps referring to where "Tony sees himself" clearly establishes that he is in a straight line of sight with the front door of Holsten's. If you'll also notice the layout of the restaurant and the booth in relation to the bathroom when Man in the Members Only Jacket goes by, one can tell that Tony would have had to look over his right shoulder to face any assailant coming from out of the restroom. Instead, he faces straight ahead in the ending shot as he notices Meadow come through the door.
