In deed a crazy situation, but you will see that the solution is quite easy: The Euro will stay, but the Greek government will have to issue a second currency to pay their bills. Many Greek have a lot of Euro (at home or in other EU contries), but the govenment has nill... I am curious about this experiment. But it will not be the end of the world, the end of Europe or even the end of Greek.
Look at the US/Euro rate, and the gold price: It tells me that it is (still) a no event.
But One thing I am sure: It will be a warning for all the other weak EU economies to do their job properly and to clean their house!
And - in worse cae: It is good for me to have a nice investment in a safe country :-) PTK!