Throngs of technology enthusiasts are gathering in Las Vegas this week for the annual Consumer Electronics Show, a blaring whirlwind of gadgets and doodads.

CES, as it is called, generally sets the agenda for the technologies and trends that will be hot this year. The show may be losing some of its importance, however. Apple (AAPL) doesn't attend, and Microsoft (MSFT) will pull out after this year. (Microsoft owns and publishes Top Stocks, an MSN Money site.)

Even if this year is the last hurrah, it's worthwhile for investors to note what the show is highlighting. Here are the hot topics:

Super-thin TVs
Never heard of OLED television sets? You will. The technology is all the rage at CES this year. OLED stands for organic light-emitting diode, and offers high-resolution screens with no backlight -- which enables better colors and truer blacks.

No backlights means that OLEDs can be ridiculously thin and light. LG has unveiled a 55-inch television that weighs just 16.5 pounds and is only 4 mm thick. The company wouldn't announce pricing for the set, which is expected to become available late this year or early next year, but word on the street puts it anywhere from $8,000 to $10,000.

OLED technology is making its way into phone screens, such as a new model for Europe from Panasonic, and possibly some tablets as well.

The rise of ultrabooks
Everyone's tried to go after Apple's iPad, with no luck. Amazon (AMZN) was the only company to produce a credible tablet rival last year.

So now the industry is turning its competitive focus to the Macbook Air. CES is expected to show plenty in the way of "ultrabooks," which are slim laptops that are no more than 0.71 inches thick. They can't weigh more than 3.1 pounds, either.

Intel (INTC) is really driving this ultrabook development. The company makes the chips for these devices and gives manufacturers the plans to build them (with room for customization). The laptops are expected to cost about $1,000 to $1,200 -- a little too pricey to really be a mainstream hit, I think.

All the major PC makers are coming out with ultrabooks, Wired reports. And CES is expected to show as many as 50 different models from Dell (DELL), Hewlett-Packard (HPQ), Toshiba and others.

"Apple has proven that people will pay a premium for style, but only time will tell if that magic can be applied to ultrabooks intended for Windows," Forrester analyst David Johnson told Wired.

Connected cars
The dashboard has become a hot spot for new technologies, and this year's CES promises more innovation. CES is turning into a mini-auto show, reports Smithsonian Magazine.

The car that will have everyone talking is the Ford (F) Evos, Smithsonian says. Check this out:

As envisioned by Ford, the Evos would start its day while you’re still sleeping, checking the weather, traffic reports, your email and work schedule, then, based on what it finds out, tells your alarm clock when you need to get up.  It would also know what you’ve been listening to and resume playing it when you get in the car.  If conditions are dicey, it can check your heart rate and switch your smartphone to Do Not Disturb mode. Or if you’re stuck in bumper-to-bumper traffic, your buddy Evos would take over the driving and let you answer emails.  It could even direct you away from roads where pollution levels are high, then wrap things up by finding you parking space.

Where do I sign up? Actually, the Evos is just a concept car. But elements of the Evos -- and certainly the connectivity part -- are starting to show up in autos across the industry.

General Motors (GM) is debuting the "Cadillac User Experience," a technology based on an 8-inch touch screen. The device syncs with your smart phone, plays music from Pandora (P), makes calls and offers other apps.