OK, I realize I am very late to this party, but I just figured out a few weeks ago that Lord of the Rings Online has a sound filter. Lord of the Rings Online has a sound filter. You can literally open up a panel in-game, record noises around you, select and replay specific ones, and drag-and-drop those sounds into an isolation bin that will ensure you never have to hear those sounds ever, ever again.
In some games, you have to go to a lot of trouble to quash the most obnoxious sounds, using mods and .ogg replacers and so forth (City of Heroes has a lot of these!). But LOTRO has by far the best system. And frankly, it needed it. Some of the classes in LOTRO are shouty. I have happily stopped my Captain and Minstrel from their endless screaming, and now that I am mad with my new power, I’m silencing things like orcs grunting and goats mooing. I love this so much.
What should we silence next, fam? What’s the most annoying sound in an MMO?