VLC, in my opinion, is one of those programs that needs to be installed on every machine. I mean, on every machine you’d like to watch movies on. Which is easy because it works on Windows, Mac OSX, and Linux.
This program plays pretty much any video format you want, and audio files but it isn’t the perfect choice for your music management app. You can easily play a DVD, VCD, SVCD, AVI, OGG, MKV, MOV, 3GP, FLAC, FLV, and much more. It doesn’t play Real’s format since it is proprietary and Apple must be keeping it a tight secret.
VLC even lets you stream media, take screenshots of the movie, play around with the subtitle settings and do a bunch of other tweaking you want.