As an aside, why did bitcoins undergo such a tremendous deflation? IIUC the system is still supposed to be in the planned inflation phase.
As far as I can tell, the recent rise in Bitcoin prices is overwhelmingly due to speculation, and is probably a repeat of the 2011 bubble on a larger scale. If you google "bitcoin bubble", there's lots of info on this.
I'm not a quant, but if you're holding bitcoins, I'd recommend selling off half of them and then rebalancing (keeping the value of your MtGox account 50% bitcoins and 50% dollars) going forward, which basically allows you to make money off of volatility in Bitcoin (while also having the potentially useful side effect of stabilizing...
The bitcoins that I had set aside for a Cryonics contest two years ago (and were unredeemed) are suddenly worth a lot more.
Details: I had added 10 bitcoins to get things started, and there were 4.75 worth of additional donations. These were partially lost when the hosted online wallet that I was using (MyBitcoin) was hacked, but 49% was recovered. As of today, after refunding part of the donated money, it is now worth 5.2675. I will be adding from my personal store to bring it up to an even 5.5. At $140 per coin, the new total is $770.
I've decided to follow the buy-and-hold strategy for at least another year, since it worked so well. I don't have exact details on what I'll do with it, but it will not be converted or spent for at least one year, and will eventually be used for promoting cryonics in some way.
Some things I have in mind if it gets big include:
Contributions can be made to:
1Jdn36JUwvJdr3Qiie4aAseFdcoTsND9Qo
(Updated, since the previous address was attached to my personal wallet on an outdated client, which was causing money to be moved out of it by accident. The above is a brainwallet with a reasonably secure passphrase, generated using Blockchain.info.)