I've compiled the top 20 goalies with a minimum of 4000 even strength shots against. The league average over this span is .917.
Even-Strength Save Percentage Leaders since 1998-99:
Dominik Hasek's even-strength save percentage in 1998-99 was .946. That is simply fantastic, and was at least .005 clear of every other season in this period.
Tim Thomas' Vezina Trophy season was no fluke, he is a very good goalie.
Kari Lehtonen is still the most underrated goalie in the NHL. Atlanta looks like an improved team heading into next season, so he should be primed for a good season. With some better support that will help turn that terrific save percentage into more noticeable things like wins and shutouts, I think Lehtonen is capable of challenging for a Vezina Trophy.
If Miikka Kiprusoff continues his decline, he'll be falling right off this chart by the end of next season. Oh how the mighty have fallen.
Sean Burke and Guy Hebert were both underrated goalies.
Roman Cechmanek shows the perils of relying on your eyes to judge goaltending, or basing your impressions of a guy on a couple of playoff series. There are thousands of hockey fans who will tell you that he was a brutal goalie. Yet somehow over 4000 even strength shots he managed to stop pucks better than almost everyone else. Must have been one fantastic streak of luck if he wasn't that good.
More evidence of Martin Brodeur's upside-down career curve:
Brodeur, 1998-2004: .918 EV SV%, .916 league average
Brodeur, 2006-2009: .926 EV SV%, .918 league average