I have a hard time calling Peyton a choker because he's is 10 times out 10 the reason they make it to the big games and by that point that other top tier team you're going against knows if they put all the focus on him they can win. I don't see that as choking so much as being one dimensional and exposed. Honestly he is a lot like Elway in that regard.
Romo for as much as I think he catches too much flak does choke though. Yeah he is the only reason the Cowboys can even say they are in the hunt but when he goes up in the last game or two with pressure on him against not so good opponents he blows up.
Ron Washington's Rangers belong on here. 2 or 3 WS in a row with no title and hell that STL one alone shows it.
That Cardinal team was possessed by something. Forgive me for maybe being hyperbolic but I'm not sure if the 1927 Yankees could have finished them off.