Here's another reason to be cautious in the short term:
I am likely the only one here who really is retired, was short the SP500 futures in 2008 (that is, all of 2008), and is short gold now. I don't have any indicators to suggest a long term top of the 2000 and 2008 kind, yet. I do see some technical indicators such as I linked above that might suggest a short term break that could be severe, but of short duration (something like summer of 2011 or worse). I think this will happen soon, if it is going to happen at all.
If there is a blow off top coming as I, and I think Sagarin, think, you are looking at not 500 points on the Dow, but 5,000 points on the Dow in the next 1-2 years--this is a bubble and it will end badly, but not until it sucks much of the public in (again).
I sold my stock futures on May 22 and am in full vulture mode. I am looking to avoid risk in the immediate future, then looking to buy in at significantly lower prices. But if the blow off top is indeed coming, the market will know that a lot of people want a good entry and it will not accomodate them.