Media Player Classic
MS was going to retire the old windows media player (I think it was version 4?), that last one that was actually decent. Instead a group of developers bought it and turned it into Media Player Classic. Or that's at least what I was told.
As the name suggests it's bare bones classic media player, but tweaked to be compatible with any codecs/filters you use. Just play my videos, or my music files, without f-ing up or taking excess resources away from other tasks. When it comes to windows media players, it kicks ass and decimates all.
It also runs as a small standalone exe, so you can drop it on a memory stick with a few filters and be covered for all formats no matter what computer you're using, and better playback quality than VLC.