Sleek, flat-panel high-definition TVs are still sleek, flat and HD — they just aren't as sexy anymore.

For the first time since digital TVs hit the market in 2005, TV sales are dropping, the Consumer Electronics Association reports.

TV makers shipped about 500,000 fewer sets to stores in 2010 than in 2009. And they expect to ship even fewer in 2011.

Why? Because more than 70% of homes now own a digital TV, most likely a plasma or thin LCD HD display.

With consumers tightfisted, retailers' annual Super Bowl sales promotions, which close with Sunday's game, have extra importance.

"The holiday season was a bit disappointing for some retailers, so there is a little bit more inventory that they have to clear though before they can bring in the new 2011 models," says Paul Gagnon of DisplaySearch.

That could mean major markdowns for customers.

Best Buy, which had double-digit percentage declines in TV sales in December from the year before, has 35% to 40% off some Samsung and Sony LCD TVs.

Sears has similar deals, including 50-inch Panasonic and Zenith plasma TVs for less than $600.

Wal-Mart has also lowered prices.

As TV prices have dropped, consumers have gotten savvy about waiting for special promotions.

Deals drove recent holiday TV unit sales up 5% over 2009, according to The NPD Group. However, TV sales revenue was down 2%.

Pre-Super Bowl specials are expected to drive similar sales bumps.

As many as 4.5 million consumers were considering a new set before the game, the most in five years, a Retail Advertising and Marketing Association survey last month found.

"We've always seen the Super Bowl as a sales driver," says CEA's Megan Pollock.

To stimulate 2011 sales, TV makers are including a variety of new features in models on the way to stores.

Vizio, for example, has a new wider-screen TV due the second half of the year (no price yet). It has a 21-to-9 width-to-height ratio (typical widescreen sets are 16-to-9). The extra width leaves room to run apps next to full widescreen video.

Sales may not be rising as they did in the past, but customers still bought about 34 million sets last year, says Jay Vandenbree of LG Electronics. LG has a 72-inch 3-D LCD TV (no price yet) due in the second quarter.

"That is still a big positive thing in the industry," he says. "I think as an industry if we focus more on the consumer and less on the technology it would be great for everyone."