High-definition TV sales were humming nicely up until last month when they hit a speed bump. Still, the percentage of U.S. households with an HDTV has doubled over the last two years: An estimated one-third of all Americans now have an HD TV, according to a Leichtman Research study.

And the HDTV shopping spree isn't over yet, according to the survey. Among those with HDTV sets, 33 percent said they have more than one, and 25 percent are likely to buy another HDTV in the next year.

"About 40 million US households now have at least one HDTV set, and LRG forecasts that this number will double over the next four years,” said Bruce Leichtman, president and principal analyst, in a prepared statement. "While more people than ever before have HDTV sets, educating consumers on HD programming remains an issue."