media player classic,extra player,kmplayer邊個最好?

The three multi-media players you listed are freeware. They all support many video formats, including the formats you listed. There are a few things to be noticed:

Media Player Classic

圖片參考：http://upload.wikimedia.org/wikipedia/commons/a/a2/Media_Player_Classic_En.png

It uses least system resources amongst the three players because it provides the least functions. Simple interface and fastest reponse time. But its latest version was released in March 2006 that no further development can be forseen.

ExtraPlyaer

圖片參考：http://www.atlas-zone.com/software/pix/ExtraPlayer/Main.gif

It is the only one that provides the powerful function of video conversion amongst the three players. However, F-Secure Online Virus Scanner reported that it contains a backdoor virus.

KMPlayer

圖片參考：http://www.kmplayer.com/forums/gallery/files/1-phoxo6_Io0_vista_glass.jpg

Although it is originated from Korea, its Traditional Chinese interface is very good. Although it provides no video conversion, it has lots of video functions that are extremely useful and powerful. New versions are coming.
In summary, I recommend KMPlayer. Please download it from official web site only. Other sources could be unreliable. Its official download hyperlink is here.

【軟體名稱】： 最好KMPlayer v2.9.3.1324 官方多國語言版
【檔案大小】：11.9MB
【放置空間】： Badongo
【解壓密碼】： kakmj分享於微風論壇，請勿盜連



【軟體介紹】：多媒體播放器，免安裝任何Code就能播放各種格式的影片


KMPlayer v2.9.3.1324 官方多國語言版