Sell high, buy low?

As gold and silver appear to be coming off last year’s lows, with both up nearly 7%, the sharemarket looks more and more near its top.  Something usually triggers a fall and right now we have a cocktail of issues as the world struggles with the concept of tapering.  The graph below shows that the US stockmarket is certainly stretched beyond the 2007 peak and getting close to the 2000 peak.  At this 15 Jan 2014 snapshot it was 12% above the 55 week moving average (blue WMA) which itself was 20% above the 200 (red) WMA.  2007 was 8.5% & 14.5% respectively and 2000 was 14% & 29.5%. The question is do you prefer buying after a market correction or just before it??