There is about $9 Trillion of M2(cash plus money in savings,checking and small CDs) money in the USA. So with simple some simple math
$9,000,000 Million / BTC 21 Million(total bitcoin ever to be mined) ~= $428,000 / BTC
So if bitcoin replaced all of US dollars, 1 Bitcoin would have the same buying power as $428,000 does right now.
If Bitcoin replaced 1% of US dollars as a currency, 1 Bitcoin would have the same buying power as $4,280 does right now.
Something to think about.
Yea even at it's "current" value of about $2, that's twice as powerful then most currencies in the whole world.