I usually don't play with sound on - most of the in-game music I've heard time and time again, and usually I'll have a DVD or MP3s playing in the background instead. But my first runs through Ahn'Qiraj, I turned the sound on to see what it was like - and it did not disappoint. Most intriguing of the sound effects are the soft whispers (presumably from C'thun) that are so faint, you might miss if you weren't paying attention (and you may wonder if you really heard them afterwards). The fact that they don't show up in your chat log (like the chatter you get from every other boss in the game), increases the creepy factor, but does it discriminate against deaf players? The fact that the whispers provide a huge source of the area's ambiance means anyone unable to hear is left out.