While I don't think it was directed at me, I'd like to address the compassion issue.
While I think it is indeed necessary and right to discuss and if possible mitigate the human cost here, I also think that any "technical" solution that rolls back the blockchain or otherwise messes with the internal working of Bitcoin is NOT compassionate, even though it
appears to be. Because if we do that (and the nature of bitcoin makes it so it is ALL of us if it is to be done), then instead of 6 percent loss, it's one hundred percent. I understand that the op was in fact not suggesting this, but rather trying to find a way to recover the keys. But the idea nevertheless got floated, and in more than one place.
I would suggest that all those who lost money in whatever flavor to MTGOX contact the court officers who are investigating the alleged bankruptcy and DETAIL your losses, with such details as they need to prove it. I doubt that the software and user accounts have been destroyed, and the missing coins do exist in the blockchain. I'm not a cryptographic expert. It's something I have some interest in, but my math skills are sub par. I'm good at merchant's math, but not the advanced stuff. Nevertheless, with the experts and the law all on this, it is likely that a fair amount will be recovered and disbursed to the account holders. I very much doubt that Mr. Karpeles personal fortune will be greatly impacted by this, unless he was foolish enough to keep his personal funds on the exchange and/or is found to have perpetrated or been involved. But his company is going to be either sold at auction piecemeal, or be bought out (price of which would likely include settlement of accounts to the extent possible).
While not physical, Bitcoin shares far more in common with hard monies such as gold and silver than it does with modern fiat currencies. It has to be treated as such. You, me, every bitcoin user needs to understand this. You HAVE to have sole access to your private keys at all times, and if you do have coins on an exchange, it should be a fraction of what you have, or be there no longer than it takes to effect the exchange. I think the people who got burned will learn this. I know it kind of came off like I was saying "they got what they deserved" earlier, but that was not my intent. I have personally lost a small fortune due to similar mistakes in my youth. If you learn from it, it's a painful memory. If you do it a second time, then yes, it is your fault.
I also think there is an opportunity here, and I would encourage former holders of Goxcoins to look into this, of offering insurance to the bitcoin market. One can mitigate quite a bit of risk in that manner, by risking a bit more on insurance
It's a rather old economic model, and one that works. An honest insurance company (they do exist, or at least have) makes a lot of money for it's operators, and mitigate risk in a manner that encourages commerce and discourages stupidity while protecting it's clients against exactly the kind of crap that just went down with Gox.
I guess what I'm saying is that I think the most compassionate thing we as a community can do is encourage those who lost out to be more careful in the future, and to help build the value of the brand. In adversity lies opportunity. It is my belief that so long as we don't allow our feelings to overcome our logic, that bitcoin and BY EXTENSION it's holders will not only survive this, it will become stronger. Mtgox is not bitcoin, much as some of the media would like it to be. It was a corrupt and incompetent company that traded in bitcoin.