Not sure how you can accept Bitcoins as a payment form, unless you tie it expressly to another currency. With this much fluctuation, the only other option would be an auction.

I think this makes it likely speculation is the only driving force for the value of a bitcoin at the moment, which doesn't bode well for something that wants to be a currency.

Edit: To be clear, what I mean is that normally we sell things for say, $2 and rarely adjust the price (a few times a year is unusual, usually it isn't even that quickly). You would need to constantly adjust your selling price in Bitcoins, making it very hard to use as an actual currency when the perceived value goes up this quickly.

Gasoline is one of the few things we buy that fluctuates pretty rapidly, and when it fluctuates people that own gas stations are often squeezed, sure they have a tank of gas they bought for say $3/gallon, but they need to schedule the next tank at $3.25/gallon, so all the profit from the current tank of gas is going to the next fill up. And when the price of gas drops, if they can't sell their $3.25/gallon gas quickly enough, they take a loss. For small stations operating on thin margins, this can wreck a month of profits.