Windows Media Player with Vista Codec Pack is good enough for me.
I like to keep everything in top notch and having all the video thumbnails inside the Videos folder is a must. You need a proper codec pack or at least the individual codecs of the video formats you have, for the video thumbnails to show up in Explorer.
Otherwise, I would like JetAudio. It is a class app, but I don't require it because WMP does most of the things that JetAudio does. Only thing I miss from JetAudio is the ability to continue a video from the place you last stopped it, even after closing the player. And also JetAudio used a lot less RAM and CPU cycles than WMP and even the shabby looking VLC player last time I checked.