If we knew the total number of active BTC holders, it would help too (in relation to the market cap). 

How many active BTC'ers are out there?  When I watch the trollbox on btc-e, there are so many screaming folks, and a lot of them surround
holdings of .5BTC or 20 LTC or ... you get the point.  While their activity can set the tone of the market, a sale at $40 shows up on the chart whether it was for .1 of a BTC or 100 BTC.  The real question is, how many BTC folks have holdings of 100, 500, 1000 and so??