Often times, a quarterback's career is defined by his ability to perform in pressure situations. These situations could range from picking up a key first down to winning a Super Bowl title. The best quarterbacks in the game are capable of winning a game on their own.
Ranking the most clutch quarterbacks in NFL history is a tough task. All the top-level quarterbacks have shown the ability to make plays in the clutch. The key is determining what performances are more impressive than others.
For example, a key drive in a Super Bowl will out weigh most other situations. However, leading your team to the Super Bowl several times, but not winning, could also be impressive. I did my best to use key situations and entire body of work. Also, keep in mind that I didn't have the pleasure of watching all of these quarterbacks play.
Nothing can replace the feeling of watching a great quarterback work his magic, as it happens. So of course, a lot of you will disagree with my list. Feel free to talk about some players I might have missed in the comments section.