Th problem with bitcoin, if nothing else, is that the exchange market, USD:BTC is rather illiquid. Doesn't MTGOX take forever to process the withdrawals in USD?

This is a big problem that does make it a toy currency. The slow exchange probably brings up the price. I expect, without much proof, that the USD:BTC ratio would be lower, at least short term, if you could exchange them easier.

$2b in circulation is pretty decent of course, but if you cannot convert those BTC to USD with ease then the valuation is flawed.