If the economists at Merrill Lynch & Co. are correct, the U.S. economy will average only about 3% inflation-adjusted growth through 2010. One reason: "Real consumer spending is likely to average about 2.5% over the next five years -- a far cry from the 4%-plus heydays of the late 1990s," says New York-based Merrill.

Its latest five-year forecast projects, following 3.3% real GDP growth this year, 3.2% in 2006, 2% in 2007, 2.2% in 2008, 3% in 2009 and 3.5% in 2010.

Worth noting: Merrill foresees the business sector of the U.S. economy doing a bit better than the economy as a whole. "Businesses are awash in cash, and years of aggressive capital investment have yielded steady productivity improvements. All of this has kept costs low and profit margins elevated -- a trend we expect will continue," says the financial firm. "To be sure, the slow pace of consumer spending will keep a lid on capex growth for expansion purposes, but the ongoing need to replace worn out capital will keep capital outlays in positive territory."