[Breakthrough]

Totally agreed, but I think it's worth pointing out that you could technically "own" the Bitcoin "printing press" if the $BTC distribution is skewed drastically to a particular majority (who could then corrupt the protocol/subsequent block chains). This is why initially, many people were told to use different mining pools or exchanges, as I recall there were a few majority cases a year or so ago (even Mt. Gox still handles > 50% of trading volume every day [1]).

That being said, assuming that everyone plays fair, uses common sense, and keeps the Bitcoins distributed fairly evenly, there shouldn't be a problem (after all, that is how Bitcoins were designed).

[1] Bitcoin Charts, "Exchange volume distribution." http://bitcoincharts.com/charts/volumepie/

[theorique]

assuming that everyone plays fair, uses common sense

Big assumption.

[Breakthrough]

+1 for pointing out the fallacies of human nature... I totally agree, this is probably the most dangerously evil assumption in the underlying Bitcoin implementation.

One I would argue is a necessary evil.

[jeremyjh]

I've seen estimates that you could execute a continuous 51% attack for as little as 80 million in hardware. That's quite affordable to any central bank that feels threatened. I think a couple weeks of this would destroy all confidence in BTC.