Daum PotPlayer is a pretty awesome free media player for Windows. It can play nearly all media files without requiring additional codecs yet supports OpenCodecs and can install extra codec packs automatically. It's easy to use yet rivals complex open-source projects in features and options.
Setup options: PotPlayer's installer tree view makes it easy to select options like File Associations, Visualizations, Shortcuts, and Subtitle Formats. We could also install codec packs during setup.
Good looking: There's nothing unique about PotPlayer's dark default theme, other than it's attractively rendered (and re-skinnable, too).
Performance: PotPlayer supports: DXA, CUDA, and QuickSync; multiple types of 3D glasses with various 3D output formats; HDTV, DVD, and TV devices; seamless playback of damaged files; and more.
Audio options: PotPlayer supports multiple audio streams; choice of sound card, output mode, and format; output resampling; and S/PDIF outputs taken before or after AC3 and DTS processing.
Aspect ratio: PotPlayer's Default aspect ratio setting is Free, which fits the video to the window shape, yet in the video settings, Fit to Video is Recommended. Surely the Recommended setting should be Default (and vice versa).
Fiddly: As we noted above, PotPlayer has a lot of options, some of which might be challenging for inexperienced users.
If you thought you'd seen it all in free media players, have a look at impressive Daum PotPlayer.