What Willi said.
I usually don't respond to XBL trolls, except with a well-placed cutting remark (which gets them to turn their endless stream of profanity toward me) and then I just laugh at them for the rest of the game.
Worse is when those douchebags are on MY team.
I admit I can probably get annoying. It used to be that I never uttered a word when I died, but after several years of dorm room gaming with friends surrounding me, I've grown into the habit of verbalizing frustration at a loss. I'm trying to cut back.