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KMPlayer is a lightweight audio and video player for Windows that supports a wide range of different file formats, including AVI, ASF, WMV, AVS, FLV, MKV, and many more.
Features
KMPlayer has a small desktop footprint and its minimalist interface makes video playback quick and hassle-free. The player's interface is fully skinable, and there are some nice aesthetic touches, such as the changing of colour on the player with every new track.

There are all sorts of options to help you pimp and customize KMPlayer, such as visualizations, plug-ins and playback options. But the beauty of KMPlayer is that these are turned on at your request rather than being forced upon you at the outset.