Having said that, I don't believe that it will go back up, most speculators will probably be ready to sell after today. It's also hard to say though, because it looks like the volume of bitcoins traded today are equal or less than other days. I can't say for sure, because Mt. Gox isn't loading properly and I'm looking at an unfamiliar set of graphs.
People keep talking about the bubble bursting. Most people don't realize that last time bitcoin flopped, it only lost 30-50% value initially, returning to a value that was still higher than just 2 months before the crash. Bitcoin spent 5 months in a steady decline, not 5 hours. Most early speculators made a profit, even if they couldn't sell until after the crash.
As much insanity as people are predicting, everything will probably be drawn out. If you have bitcoins and are nervous, now is a fine time to sell. If you think bitcoin will keep going up and you bought more than 30 days ago, you will probably be able to come out ahead even if you are wrong.
But you have to appreciate that most of Bitcoin is speculation. Bitcoin seems safe because it is inherently deflationary. That brings an unproportionate amount of speculators to the currency, and causes the deflationary properties to exaggerate. After enough time, the currency will become clearly overvalued. The free market will take care of that in a cyclic fashion.
As long as Bitcoin is used by people for it's anonymous and cryptographic properties, it will be subject to this hyperdeflation/crash cycle. The exiting bits don't last long and ultimately don't make the currency gain or lose terribly extraordinary amounts of value. After a crash, I'm sure bitcoin will still be worth at least $60, which is still fantastic if you bought back when it was less than $15.