Of course, a default is never a pleasant experience for both creditors and debtors. Nevertheless, there is life after a default. A country that is 'bankrupt' does not cease to exist. It doesn't evaporate. It's still there, albeit usually living on a more modest budget than before the default.
By the way: if Greece defaults, absolutely nothing happens to the euro. A Greek default cannot bring about the end of the Euro Area. The existence of the common currency is simply independent on the credit quality of any of the member states. Even if Greece, Spain and Portugal defaulted on all of their obligations at once, the euro would still be there and fulfil the role of common currency.
The euro could only be destroyed if all of the member states would deliberately leave it in favour of a newly minted national currency. A highly unlikely event indeed: Greece simply doesn't want to change the euro for a new drachma.