Another possible factor in a resurgence of lighter laptops is people's own buying choices after living with desktop-replacement models. Sony's Abarri noted that many of the company's lightweight laptops are bought by second- or third-time buyers.

Some industry figures think the era of desktop-replacement machines will reach an endpoint because of the laws of physics alone. Future generations of desktop processors will probably be so much bulkier and give off so much more heat that they may not be usable in laptops at all.

"It's getting more difficult to deal with, from a development perspective," said Jonathan Kaye, manager of product line marketing for laptop computers at Hewlett-Packard.

Kaye thinks that manufacturers will eventually need to resume building laptops around processors designed for use in portable computers. He, however, doesn't expect to see this emerging as a trend for another year or two.

By then, thin-and-light laptops may face still stronger competition from increasingly capable gadgets that weigh still less and usually fit in pockets instead of briefcases or purses: cell phones and personal digital assistants.

Computer makers all say that they are more concerned about competition from other computer makers, not from such pocket-sized gadgets. Kaye cited reports from market analysts at IDC, which forecast that the laptop market will grow 21 percent this year in the United States.

"I don't see [mobile gadgets] impacting us yet. At some point, maybe," he said. As more than one marketing executive pointed out, you can check your e-mail on a BlackBerry, but can you create a PowerPoint presentation on it?

(A handful of computer manufacturers are readying ultra-light laptops; a San Francisco start-up called OQO, for example, plans to ship a paperback-sized, 14-ounce laptop this fall.)

Back in the here and now, if consumer-oriented machines generally aren't getting any smaller, they're also not likely to grow any bigger. There seems to be a limit on how much screen people want in a laptop: Despite the appearance of some models with 17-inch screens last year, 15-inch screens still hold about 80 percent of the market, according to the NPD Group, a research firm.

No one interviewed for this story brought up the prospect that users will one day lug around a laptop with a 19-inch screen.

Deep-pocketed users looking for a brag-worthy option to add to their next laptop just don't have much to choose from this year. Some makers, such as HP and Sony, are offering screens that they say are brighter and have richer color than traditional laptop displays. On one high-end laptop, Sony has included a tool that determines how dim or bright a room is and adjusts the screen brightness accordingly. Neat, but then again, this is a $2,799 machine.

Users looking for something new and different might also turn to Tablet PCs, a variety of laptop running a special version of Windows XP that allows users to write data directly onto the screen. But those computers haven't caught on among consumers yet, and most business users have shied away from them as well.

The more interesting technologies seem to be much further down the line -- to judge from the way manufacturers say they are "tracking," "working on" or "researching" them, instead of adding them to upcoming products. The most intriguing such contender: fuel cells, a new type of power source that could last far longer than the batteries in today's laptops.

But don't expect to trip over such models in the aisles of your neighborhood electronics store any time soon. The next wave, the one that will again stir up consumer confusion and purchase anxiety, seems safely distant.