I'm a die-hard Rangers fan, and have a ton of games that I can list here, but I'll narrow it down to the top two, and they're both easy. They're also both from the same playoffs.
Game 7 against the New Jersey Devils in 1994 is my all-time favorite. It didn't get us anything other than the trip to the Stanley Cup, but it's hard to put anything in the same league as this game. It went to multiple overtimes, and ended on the most improbable shot, from the most improbable source. "Matteau! Matteau! Stephane Matteau!" is a call that will forever bring tears to the face of Devils fans. Brodeur was a god, but was outplayed by Richter, and the entire team put on a tremendous showing.
The second, is probably the game that everyone would think would be #1. That's Game 7 of the 1999 Stanley Cup Finals against the Canucks. No one can deny that this was a great Stanley Cup. It was good old-fashioned hockey, and had some of the biggest names in the sport. Pavel Bure, Mark Messier, Mike Richter, Adam Graves, Trevor Linden, and Kirk McLean were all on top of the league at this point. Everyone knew going in that it was going to be a series for the ages, and it didn't fail. This game capped off a tremendous series, and ended the 54 year drought for all of us Ranger fans.