DOW 15,000 is beyond the realm of possibilty, at least for the next 5-10 years.
We had the biggest bubble in the history of this country. The DOW topped at 11,750. For it to eclipse this only 3-4 years after a major bubble top would be unprecidented in market history. Greenspan can print money until he runs out of trees; it can't outweigh powerful historical trends that are not in the markets favor.
Consider all of the good news that is currently priced into the market. High GDP growth, low inflation, high productivity, job "creation" (dubious at best).
I like DJX put options here at 10,000. Specifically June 2005's. You could buy the June 104's for 10.20. That would put your break even point at about 9400. A 6% decline in the market between now and then offers high probability IMO.
The 2005 economy won't be a pretty picture.