Well Buddy, i had tried a lot of them.. but i must say that Media Player 11 rocks... it is the best one in the market rite now... I always looked for the Library function in a player... Media player 11 gives the best library utility.... Also, if you are short in memory or low processor, try Foobar 2000, it is too good... very low memory consumption, the least of all, and processor... it gives a lots of facilities... just check it out to get the glimse of what i m saying...
The advantages of media player comes from the fact that media player is kind of in built in the OS. So it has got a lot of support from the kernel and thus a lot faster in decoding than other players which are nothing but applications. But if you are talking of portability, support of various file-types, open-source, ... VLC rocks. You will say that you can install divx plugin in Media Player to play divx encoded files. But in VLC 1) youdon't nedd to install anything and 2) It's way faster than what media player becomes after 3rd party enhancements.