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??
I have seen a couple of fun graphs which try to plot wallet sizes against the number of wallets. I doubt their reliability though as they showed a cutoff with the top 1% of all wallets containing more than about 120 coins. And a totally huge number of wallets at less than 1 coin (more than half of all addresses from what I recall).
Perhaps someone knows more about digging these statistics up from the blockchain, i'll give it a try but I doubt i'll succeed.