[flyhigh]

That's a loaded question and there have been many threads on this. A lot of it just comes down to personal preference for features you might deem important that others won't. Search around and install and try as many as you'd like, especially if they're free or have a free trial period. Keep what you want. I would recommend Kinoma Player (they have a free version). I love it because it ties into Orb so well and also offers a lot in the way of streaming media. Some other popular players are Windows Media Player (which is also on your device) TCPMP, Core Player, Pocket Music, Pocket Player and S2P. I'm sure I left out a few but that's what's popping into my head. Search here or google for them.