VLC Player

VLC (initially VideoLAN Client) is a highly portable multimedia player for various audio and video formats, including MPEG-1, MPEG-2, MPEG-4, DivX, MP3, and OGG, as well as for DVDs, VCDs, and various streaming protocols. It also can be used as a server for unicast or multicast streams in IPv4 or IPv6 on a high-bandwidth network.
VLC is quick and easy to install. You can make VLC your default media player for various (or all) file types, but if you just want to try VLC without giving up your current player, you can skip the file associations. We clicked the familiar orange-and-white traffic cone icon to open VLC's famously plain interface, which is also a model of efficient layout design (and completely customizable, in any case: clicking the skinned player option in VideoLAN's Start Menu folder opens VLC in a sleek new view).