The fact that we were/are starting this process with sky-high valuations for stocks, bonds, and housing makes me less concerned about missing the eventual bottom. A trailing S&P 500 PE ratio of 18 is a bit rich for an economy that was struggling to hit 2% growth pre-crisis and has entered the early stages of unprecedented unemployment, worker disability, bond and consumer debt defaults, small business closings, collapse of entire industries (oil, hospitality, travel, tourism, and malls in the first wave), deflation, and who knows what when it comes to the banking system.
If the trailing PE right now was 10 or 12 - common S&P PE's in the past - I would be nervous about a reversion to the mean around 15-16 someday. If this turns out to be the bottom at a trailing PE over 18 and a forward PE of a very large number, I'll shrug my shoulders, hold a bond portfolio, and watch for the next correction. Circumstances justify bargain prices for stocks, and we're not there yet.
We are now finding out what those forecasters meant over the past couple of years when they said we should expect stocks to return just 4% over the next decade, just based on valuation. People mocked them too. But people always say valuation doesn't matter near a top.