I prefer the combination of Media Player Classic (MPC) and ffdshow. Media Player Classic has a look more like Windows Media Player 6.4 (the last good version), and ffdshow is just an alternate packaging of the same set of codecs that power VLC.

MPC also has some interesting features that are of use to me. It has an option to set the playback of video at a higher than normal priority, which helps keep things running smoothly. There are keybindings for adjusting the audio sync, I can use both ffdshow based codecs AND the originals, since I am able to disable or set priority levels on which codecs should be favored over others. It's also really small. Not that VLC is any slouch here, but its cross platform nature makes for some additional overhead MPC doesn't have.