Mt.Gox is giving a high of $266 and a low of $105 right now, so in that sense it's lost ≥50% of its value already. But that's exaggerated by cherrypicking the high & the low, and the exchange rate's hovering around $170 now. We'll have to wait and see whether it returns below $130ish and stays there.
It collapsed again during the time it freakin' took me to get back home from university, during which I had 0.42 bitcoins on bitcoin-24.com (I'm not crazy enough to play with more money than that), but now it's back up. (Mt. Gox seem to be down at the moment and I don't dare imagine what happens when it's back; I'm selling some of my bitcoins in case they collapse, but not all of them in case they skyrocket again.)
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(Updated, since the previous address was attached to my personal wallet on an outdated client, which was causing money to be moved out of it by accident.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.)