I had a game earlier today.
VIP Sandtrap Covies
When the gametype loaded up, no one complained. A few people vetoed. When it was accepted, someone on our team said, "Good luck, Blue." A guy on the other side said, "You too, Red."
We won. In the post game lobby, several people said, "Good game!"
Probably 1/3 of my games are like that. In most games, there's just one or two people yelling, and I mute'm instantly. Then they sound like this one. Civil, with nary a mention of testicles or racial/sexual preferences.
In the interest of a contrary viewpoint of Halo 3 online experience.