I use VLC and have never had an issue with it. Does exactly what it needs to and I have not come across a file type which it wont play yet
My favorite for movies is VLC, although it takes too long to load. I usually stream movies anyway. Actually, I stream music too with Spotify.
VLC player is the best i like because it can play Videos of any format whether its avi, vlc, wmv, rm or mpeg etc.
I use Windows Media Player for music and Media Player Classic for videos on my PC, and winamp and MX Player on my android smartphone.
Although I use Media Player Classic sometimes, the one I am most comfortable with is VCL player. I am yet to find something that cannot be opened with it.