Good choices so far. My hope is that people can start naming great performances on their own teams and we can go from there.
Some games by Bruins players over the years that I think deserve recognition:
Patrice Bergeron, Game 7 ECQF vs. Toronto in 2013 - 2 G, 1 A, 3 P, +3, 16/22 faceoffs. Assisted on the 4-3 goal with 1:22 left, scored the the game-tying goal with 51 seconds left, then won it in OT.
Tyler Seguin, Game 2 ECF vs. Tampa Bay in 2011 - 2 G, 2 A, 4 P, +3 in 13:31 TOI. Major breakout with Bergeron out, and all of his points (and especially goals) were on highlight reel plays.
Brad Marchand, Game 7 SCF vs. Vancouver in 2011 - 2 G, 1 A, 3 P, +3. I think Bergeron, Thomas and Marchand had great games on the biggest stage, but I have to single Marchand out. Great pass on the GWG, amazing effort on his first goal, and put the nail in the coffin with his ENG. All along with being a key component on the line that made the Sedins a -4 on the night.
Tim Thomas, Game 2 ECSF vs. Philadelphia in 2011 - 54 shots, 52 saves in a 3-2 OT win. Probably the best performance on his historic Cup run. With a 1-0 series lead, Philadelphia completely took it to the Bruins in this one, with Thomas really being the only reason they won. After being tied at 2 after 1, Philly outshot Boston 32-10 in the 3rd period + OT, with Thomas making a countless number of his athletic saves to get the very important swing game in the series.