I'd agree that some here are a bit too CERTAIN the market will tank in the immediate future; I think that there is the distinct possibility that the predictions of 15% growth in equities next year might well come true. But…
MMFs are paying over 5% and have very limited risk (variability). Stocks MIGHT make 15%, but they might also go down considerably as well. Add up the possible outcomes and weighted averages however you'd like, I don't see too much downside to sitting outside of the market for a bit.
In a year one of us will be right. If you are, then you've gained something more than my 5%. If I am, drop me a line and I'll buy you lunch with my earnings.