I wanted to start from the basics on goaltending and estimate how many wins a goaltender can be worth to his team. I looked at 5-on-5 and 4-on-5 save percentage only (no shot "quality" adjustments), relative to replacement, and assumed every goalie was average at 5-on-4 (given that they face so few shots). I'll make the appropriate adjustments as I expand on this topic.
The key insight is that the absolute best goaltender in the league in terms of performance over the last two seasons - Tim Thomas - was worth about 8 wins above replacement per 82 games. Goalies never play 82 games, so their real values are slightly lower than that, but this puts us in the ballpark. You may disagree with where I put replacement level, but if it was any higher, Miikka Kiprusoff would be right there, and I don't think that's quite right.
Here's the piece: