Next week is Macworld, Apple’s annual trade show in San Francisco, and, predictably, rumors of technology announcements are plentiful. This year, the technology speculation revolves, as usual, around a few likely and dull candidates, such as upgraded Mac minis and quad-core iMacs; a somewhat likely announcement of an iPhone nano; and the long shot of a large-form iPod touch.

Of course, the touch-tablet idea has people the most excited. The market for netbooks–parsed-down laptops that connect to the Internet–has exploded in recent years, with companies like Asus and Dell leading the trend. And the popularity of Amazon’s Kindle e-reader shows that people are interested in reading content on a portable gadget.

Apple has the perfect collection of assets to produce a slick competitor: its touch-screen technology is one of the most intuitive and reliable available; its combination of iTunes and App Store makes buying music, games, videos, and software easy; and its star power can convince the public that a touch tablet will be the next must-have gadget.

While hopes are high for the technology coming out of Macworld, this year’s show has a different tone from those in years past, as the honorable Steven P. Jobs will not be presiding. Instead, his sidekick, Phil Schiller, senior vice president of product marketing, will take the stage for the keynote presentation.

This news, announced before Christmas, led, of course, to immediate speculation about Jobs’s health. He’s a survivor of pancreatic cancer, and in the past year or so has looked thin and unhealthy in public appearances. PR flacks have insisted that the change in the Macworld lineup–Jobs has been giving the keynote since 1997–is because the show isn’t as important as it once was for launching products. Indeed, there will be no keynote by an Apple representative next year.

Still, yesterday, a post on Gizmodo cited information from a “previously reliable source” saying that Jobs’s health is failing fast. The news led to a dramatic drop in Apple stock.