So the BTC-USD price at MtGox and the BTC-EUR price at BTCex will inevitably reflect the global USD-EUR price.
Not true ... BTC is global and there are about 10 TIMES more people on the rest of the plant than in the U.S. plus
the U.S. dollar is practically worthless now. The sheer amount of people that will be using bitcoin on the rest of the planted dwards the US market .. so it should NOT be put against a dead/dying currency that is no longer accepted in so many nations (including large parts of it's own)
It should be used as a currency of it's own .. but for those more interested in Fiat it should be traded at it's LOCAL value, not the U.S. value.
I'm noticing also .. another trend I find weird .. and kinda disturbing ... everyone that buy bitcoin asks how many bitcoin for X Fiat .. as if the value of Fiat is static and bitcoin changes ... shouldn't that be the other way around .. if your using bitcion as your primary currency .. then IT's value is status and FIAT should change ... know what I mean.
There's no such thing as local value. Forex is a global market. If it's possible for someone to profit from arbitrage, they'll do it.
I appreciate that you regard the USD as dead or dying. I feel much the same way about my own currency (GBP). But we're a small minority in a vast, global and free market. Forex is the largest and most liquid market in the world: last year the daily
turnover was $4 trillion. That dwarfs bitcoin.
It's usual in forex to consider how much one currency buys. For example, in USD trades they're typically quoted in terms of how much non-USD can be purchased (the exception being GBP, for historical reasons). It's the same with BTC: because we tend to regard that as the more important of the two pairs, we consider how much of the other currency we can purchase for 1 BTC: 1 BTC = 0.7905 USD, 1 BTC = 0.5804 GBP, etc. I don't see that as a bad thing.