I have only ever encountered this crash when playing multiplayer, from what I remember. I may have encountered it alone once, but I know at least three times during multiplayer this has happened.
Every time I have had this crash occur, the screen will freeze, the sound will tick every second or so, (including the voice of the people I am playing with being stuck in the tick-tick-tick sounds), I cannot dashboard or do anything but power off the console, and even that takes about 15 seconds before it will shut down. I can power up and play again, but it will happen again.
I had been playing for about 2 hours when it happened today. The XBox is well ventilated (I checked that thread the last time this happened), it is not hot by any strethc, and this never happens in any other games that I also sometimes play for more than 2 hours at a stretch, so this IS directly related to Diablo 3, and not a system issue.
Thank you for your attention in this matter. An update on why this happens to so many people and a fix for it would be greatly appreciated!