Stock market investors who think market peaks like now are good times to add large sums to the equity side might want to consider what would have happened had you gone all in with new monies in the spring of 2000.
Today's real S&P500 for April 1, 2000 was higher than it is today: 2,022.46 then vs. 1951.27 now. The real S&P500 would go on to exceed that level only once: on August 1, 2000 at 2,037.97. It's been a pretty rough ride since then even with the spectacular 5-year run we've just had, added in.
Ironman here provides an excellent tool to calculate your returns in the S&P500 since April 2000 to April 2014, the most recent date available. They are horrible: just 1.3% per annum real, 3.68% not adjusted for inflation.
By way of contrast, Morningstar reports that Vanguard's Total Bond Market Index Fund through yesterday has produced a nominal 15-year return of 5.34% per annum.