Although complacency is at an all time high (and the VIX at an all-time low), a credit event appears to be looming. This means that certain companies may have cash flow problems. Keep your eye on those deteriorating CCC high yield bonds, and read my MarketWatch article (below). The market climbed 13% in a month and many are saying the market will never go down again. This is what they say at the bottom, but with an opposite prediction.
Bottom line: This is the time to get defensive, and if you are aggressive, start building those short positions. Hint: Buying puts is less risky than shorting, and if you are wrong, you know in advance how much you can lose.
Note: If this credit event is for real, even the Fed will be unable to contain the damage (but they will try).