The S&P is approaching its 2007 peak, which is basically equivalent to the peak just prior to the .com crash.
As an essentially passive index fund investor I like to take a look back at times like this:
The market stopped making sense to me around 1995 -- almost two decades ago. So I like to put a ruler on the 1980-1995 trendline and see what the S&P would be today if the market had continued to make sense.
Today I get about 1,000, so we're currently 50% above that old-timer trendline.
For whatever that's worth.