BS Player was my favorite media player, but after the last video driver update (or possibly Windows update) it's messed up. Since the user community isn't very big it's hard to find information to fix problems with and I'd like a better supported and stable player. I would mainly use it for videos and would like it to be lightweight.
One thing I like about BS Player is it can automatically search for subtitles online, download and apply them. Also I like how the playback window is separate from the control bar.