Market capitalization is a term that is usually used to refer to the total value of the shares of a company. Given that bitcoin is not a company, is there a better term than market cap that we should be using to describe the total value of all bitcoins?
The value of a commodity expressed by its exchange rate in dollars is sometimes referred to as "Total Dollar Value" (example). That's probably the most commonly used term for referring to the value of all assets at the current valuation.
Incidentally, money stock refers to the amount of bitcoins themselves. So currently (Feb 2013) there is about 10.8 million BTC.
There is another concept called purchasing power which might be used as well. Because the value fluctuates, prefixing that definition and referring to it as "current purchasing power" might be an even better term. Discussion on this was initiated in a forum thread.