With political and budgetary turmoil in Greece and other EU members intensifying, it's worth considering its effects on the broader market.
I believe the issues in Greece have been skewed. This is not a revenue crisis, rather it's a problem of failing to meet EU fiscal requirements for continued membership. This isn't even to mention the ire that's been drawn from fellow member states like Germany and France who may soon be tasked with bailing it out.
In short, if Greece is to remain a member of the EU in the long term, collective EU budgets will be strained. This will put downward pressure on the Euro currency. Conversely, a Euro unburdened by this responsibility would likely rally in response.
If the worst fear of the market right now is a Greek default, its last hope is a Greek exit from the European Union. In this event, demand for Euros would increase and likewise put downward pressure on the US dollar.
With this in mind consider that the markets often trade inverse to the US dollar (see chart). A strong Euro means a weak US dollar, and a weak dollar typically lifts markets. A Greek exit from the union would relieve investor worries of an EU collapse and make stocks and commodities cheaper to purchase. These are certainly two very bullish cases for markets going forward.
This is not to argue that Greece exiting the EU is in the best long term interest of either Greece or the EU, just that markets would--at least temporarily--interpret it favourably. Looking forward speculatively, one can envision a scenario where removing countries like Greece from the European Union acts as a last ditch bid to boost a failing market and bolster global financial optimism.
How long that optimism would last is anyone's guess.