VLC Media Player

Use – Portable media player
Cost – Free

Description:
VLC Media Player Portable is the popular VLC packaged as a portable app, so you can take your audio and video files along with everything you need to play them on the go. You can place it on your USB flash drive, iPod, portable hard drive or a CD and use it on any computer, without leaving any personal information behind.

Portable Version:
http://portableapps.com/apps/music_video/vlc_portable

Developer: www.videolan.org/vlc