Who is the best goalkeeper in the EPL? Why?

Van Der Sar isn't even as good as everyone is making him out to be. Paul Robinson is better than Van Der Sar. Petr Cech is the best 'keeper in the EPL, but not one keeper has really stood out this season. Ben Foster has had a very good season though, 3 years ago he was playing sunday league football and now he has got a full cap for england and he is starting every game for Watford. I think he will be a great keeper when he replaces Van Dert Sar when Van Der Sar retires. But i still think that Petr Cech is the number 1 keeper in the premiership.