Mike Green snapped a third-period tie, Jason Chimera scored and Boyd Gordon added an empty-net goal for Washington, while goalie Jose Theodore finished with 23 saves.
Hours after acquiring four players at the trade deadline, the Capitals ended a three-game losing streak in their first game following the Olympic break.
Miller made 37 saves in his first start since leading the United States to a silver medal and being selected the tournament MVP. He received a long pre-game standing ovation from the home fans.
Jochen Hecht scored for Buffalo, which has won only one of its past nine.
In Detroit, US Olympian Ryan Kesler scored twice, and gold-medal winning Canadian goalie Roberto Luongo made 28 saves as Vancouver downed Detroit.
Alex Burrows, Kyle Wellwood, Sami Salo and Mikael Samuelsson also scored for the Canucks.
Jason Williams, Henrik Zetterberg and Johan Franzen netted for Detroit.
In Anaheim, California, Colorado snapped Anaheim's 11-game home winning streak.
Matt Duchene scored the go-ahead goal with 11:51 to play and Peter Mueller scored in his Avalanche debut.
Chris Stewart and T.J. Galiardi also scored for Colorado.
Teemu Selanne scored his 598th goal, annd Scott Niedermayer and Jason Blake also netted for the Ducks.
In Calgary, Canada, goalie Niklas Backstrom made 29 saves for his second shutout of the season as Minnesota downed Calgary.
Mikko Koivu and Andrew Brunette each had a goal and an assist for Minnesota, while Kyle Brodziak and Martin Havlat also scored.
In Chicago, the hosts made it five wins in six games by defeating Edmonton.
Niklas Hjalmarsson, Dustin Byfuglien and Jonathan Toews all scored in the third period for Chicago.
Marian Hossa and Dave Bolland also netted for the Blackhawks, who outshot Edmonton 47-14.
Robert Nilsson and Shawn Horcoff scored for the Oilers, who have lost seven of their last eight.
In Sunrise, Florida, Florida ended a season-worse seven-game losing streak by dominating Philadelphia.
Michael Frolik scored twice and David Booth had a goal and three assists for the Panthers. Booth also fought with Flyers captain Mike Richards, whose hit in an October game caused a concussion that forced Booth to miss 42 games.
Bryan McCabe had three assists and had an empty-net goal, and Steven Reinprecht, Jason Garrison and Stephen Weiss added goals for the Panthers.
Daniel Briere, Jeff Carter, Ville Leino and Ryan Parent scored for the Flyers, who had their five-game winning streak snapped. Carter has scored in six consecutive games, tying three others for the longest streak this season.
