^ However... do NOTE that XBMC is a Media Center software, not just a stand-alone player. I mentioned it just to illustrate my point for hardware acceleration & video post-processing. OP is looking for standalone media player software like MPC or Windows Media player alike.
If you are using MPC HC, go in the settings and see if you can get the MAD VR video renderer. It gives awesome quality. But slightly high on processing.
Else, simply install KM player and see how it goes. Its a no hassle player.
+1 MPC-HC !! Supports almost all the files and provides many decoders and using EVR you can use HW accelaration in OUTPUT option !! And VMR 7 or 9 renderless for software decoding!! There is a lag when you forward the movie but VMR flows very smooth !!