Ha! I loved watching Cunningham, but I woudn't call him the greatest. But for my 3 hours, there was no QB I'd rather watch. Those Eagles had some great defenses in those days too!But for the time I've been watching football (from the mid 80s) I would say the top QBs were:
Montana
Marino
...
Elway (not in the top just caus I never liked the guy)
Young (How many years did he sit on the bench watching Montana? Immagine if he had been playing his entire career)
Favre (remember him riding the pine behind the "magic man" Majkowski, and then being the wild man who would over-throw an open receiver by 40 yards... then getting it together. He's definelty on the downside of his skills now).
...
Manning (wow - he'll keep it up too)
Brady (he does what it takes to win and almost never makes mistakes).
I think of those, Montana would be the guy I would want to QB my team. Next to him Marino. Next to those two, Brady, since he's the guy who gets it done.
I can't comment on the old timers (like Starbauch, Theisman, Starr and so on) since I never saw them play.