WM9, MPEG-4 AVC High Profile, MPEG-2 are all now supported in BD-ROM. Content creators have these 3 choices to choose from when producing a BD-ROM disc.
Xvid = mpeg4, and yes it is still the best codec you can get for your personal PC. It will be interesting to see which codec is chosen the most. I honestly don\'t care as long as it provides decent HD.