To look at Greece is to look at our future, but more immediately the future of other European countries. The decline of Europe has been documented in many places by many individuals, most notably by Mark Steyn in his landmark book America Alone.
Today there is a great article in Meridian Magazine by Larry L. Eastland about how demographics, economics, and the modern welfare state are on a crash course. At this point, it's virtually inevitable, and only drastic measures will forestall disaster. Worth a look.
Especially interesting is how he ties in the biblical idea of multiplying and replenishing the Earth, and how the failure of modern societies to follow this admonition has led directly to this crisis.