SI's Michael Farber recently gave us his all-time NHL team.
In his article, he included this interesting paragraph on the importance of goaltending:
"The goaltending position on the historical team -- or the Ghost of Christmas Goodies Past, as I like to think of it -- vexed me the most. Recently the esteemed Serge Savard, who narrowly missed making this team as a reserve defenseman, advanced the counterintuitive argument to me that goaltending is not the most important position because, in almost every case, teams make goalies more than goalies make teams. Remembering the 1999 Buffalo Sabres and Dominik Hasek, Savard still has some convincing to do."
Savard is not completely right - goaltending is the most important position, since the potential effect of a goaltender is much greater than that of any other single player. However, I generally agree that the importance of goalies is generally overstated. The position is important, but performance is actually quite similar among most goalies at the top levels, especially after removing team effects. The difference between many good goalies is just small fractions of goals per game, which means that you often need a substantial edge in the crease to make a losing team into a winner, or vice versa. This is because the rest of the team combined is three or four times more valuable than the goalie in terms of their contribution to the final result. So it is actually fairly rare that a goalie wins or loses games because of their singular efforts. Pointing out one exception to the rule (Hasek) doesn't invalidate that entire viewpoint. In fact, it is good evidence for that particular goaltender as one of the all-time greats.
I wonder what Savard thought about his former teammate Ken Dryden. If you take his statement to be true in all cases, then Savard probably thinks Dryden was lucky to be playing on the teams he did.
Farber should have paid more attention to Savard, because he picked Terry Sawchuk as the backup on his all-time team, a goalie who is very overrated because of the strong Detroit teams he played on early in his career. Farber's top goalie ever was Roy, which isn't a bad choice, but probably not the correct one, and the reason again is the hidden factor of team strength.
It is difficult to argue with choices for all-time teams, because different observers rate things differently. For example, some focus more on career numbers and longevity, while others heavily weight a goalie's prime. Some look at playoff performance above all else, while others just see it as part of the mix.
I don't have numbers yet that I believe are conclusive in terms of ranking the best of all-time. However, I think Hasek should probably be in the top spot, and would probably lean towards Jacques Plante in a very tight decision over Glenn Hall, Tony Esposito, and Roy for the #2 position.