...
http://seekingalpha.com/article/3958137-gold-bitcoin-economic-freedomThe article covers a pretty good amount of ground, including a table showing the market cap of the 10 most popular cryptos. BTC at $6 billion plus, LTC at about $1 bn.
Do seek out
aminorex's comment below the article (re Dash vs. Monero -- a topic for which I have no competence).
EDIT: the 180,000 tonnes of above-ground gold are worth some
$8.4 TRILLION (Au at market value of $1230).