In general, I play with sound off.
Basically had an issue at one point where I was crashing from something.
Adding -nosound to my executable removed the issue.
I got used to no sound in warcraft.

Then farming crap or leveling with stupid collection quests became super boring.
So had a Keyclone window set up, where I had smaller slave windows along the top.
And then two large windows (half a 30" widescreen monitor) along the bottom.
Active window in the left, and window media player for a dvd in the right.

WoW doesn't crash with sound on, but I've gotten used to having either music or a dvd going, and sound interfere's with either.