This is starting to look huge.... I don't think I've ever seen 120k bitcoins on the bid side on mtgoxlive! The ask side looks flat compared to that giant wave.
edit: Comparison of the depths:
20k BTC to 3.38, 20k BTC to 3.10
20k more to 3.75, 20k more to 3.00
Didn't we have a huge bid wall sitting there right before the last "crash" to $2?
Nope, this is what it looked like on Nov. 13th right before the crash from $3 to $2:
Then during the crash, someone instantly and dramatically popped up a huge bidwall at one point:
So yeah, one big player has a lot of cash, and all the bids could be the same big player subtlely building up the bid orders. I don't think that's the case, but I wouldn't doubt that half the bid orders is this same big player.