I am going to give some interesting points of time and history.
History repeats itself, but not exactly the same. It has cycles but not always predicable. If you are prepared for them and it happens you are OK. If not then you will be lucky or hurt.
Let's start with dates. In chronological order.
Nov 9 1903 Bottom at 30.88 Top on Jan 19 1906 75.45 144% Rise 2 years and 2 months
Jul 30 1914 Bottom at 55.32 Top on Nov 21 1916 110.15 111% Rise 2 years and 3 months
Jun 1 1932 Bottom at 4.4 Top on Mar 6 1937 18.68 325% Rise 4 years and 9 months
Apr 28 1942 Bottom at 7.47 Top on may 29 1946 19.25 158% Rise 4 years and 1 month
Jun 26 1962 Bottom at 52.32 Top on Feb 9 1966 94.06 80% Rise 3 years and 7 months
Aug 9 1982 Bottom at 101.44 Top on Aug 25 1987 337.89 233% Rise 5 years
and now
Oct 10 2002 Bottom at 768.63 Potential top om June 4 2007 100% Rise 5 years and 7 months.

Now study the dates and look for the pattern.
They all start in the beginning of the decade and stop in the year 6 or 7. Coincidence?
We are in the weakest and longest bull market in the history of the stock market.
Really the Dow has made it to new highs which is what happened in the late 60's but the Nasdaq hasn't come close. We will flirt with the highs and then another event will happen that accentuates the negative sentiment of the people which will cause a bear market to be officially declared. I hope you are protecting yourself by writing calls, and usiing close trailing stops. Go into short term money markets and wait to buy when there is blood in the streets.
Hopefully Bernake doesn't raise rates as it has been implied because it can be the nail in the coffin.