If Greece leave the EuroZone, then OMG for its population : Rampant inflation, political unrest, debt defaults and a possible "contagion" within Europe's financial sector.
The euro would be effectively abandoned, and Greece would return to the drachma, its previous currency (it might take a new name). The drachma would likely tumble in value against the euro as soon as it was issued, and how much the government could print quickly would be a big issue.
European life support for Greek banks would be withdrawn , likely unrest and disorder, Greece would resume economic policymaking, Inflation would spike immediately.
