Goalkeepers are often underappreciated until they screw up. You rarely see large transfer fees or salaries paid for goalkeepers.
This shouldn't be the case. As an old saying goes in the goalkeeping community: "The goalkeeper is the person you count on to succeed after everyone else has failed." While you can win a title without a great goalkeeper, you can't win one with a bad one.
With that in mind, here is a ranking of the 20 first-choice goalkeepers in the Premier League as of September 1. Goalkeepers that came into the league at the transfer deadline (e.g. Julio Cesar and Hugo Lloris), were not included in the rankings.