Media Player Classic will run most if not all Container files around (Mkv, avi, wmv, asf, ogm, mp4). It has support for multiple audio streams and subtitles.
FFDshow will play just about every single video codec out there, including, but not limited to, h.264, DivX, Xvid and many others. It also has support for just about every AUDIO codec out there, too.
These are practically the ONLY two programs you will need for video playback.