Media Player Classic with the K-Lite Mega Codec Pack. It has always worked well for me when playing any video. It is one of the most popular Media Players there is. It should have been one of the choices on the Poll. I use Windows Media Player for Audio files.
Back in the 90's i started using Jet Audio PLUS VX (download at MajorGeeks.com) to play music and Video files. There is also a free version of this player but i've alwaays been using the commercial/paid version. Few years ago i also installed AIMP multimedia player (download at MajorGeeks.com) on all my machines. Both players have quite nice sound enhancenmend features (e.g. mega bass).