Hmmm, there's a few things you could try.

Reinstalling the game would help if it was some texture that got messed up.

Reinstalling your sound and video card drivers would help if a driver got corrupted.

Those are the easiest things to try, and hopefully something will make a difference. I would also suggest checking out Blizzard Tech support in case a similar problem has been reported and to see if they have any recomended fixes.

A+ Certified PC Tech Guy/Seitentaisei