Brian Nadel

After more than 20 years of dragging a notebook computer around whenever I traveled, I finally told myself that enough is enough. On two recent business trips, I joined the small but growing number of travelers who eschew a laptop in favor of a smaller, lighter device.

I could have opted for an iPad or an Android tablet, which would have lightened my load somewhat while providing a 7-to-10-in. screen. But that's an intermediary approach that would still require carrying a phone in addition to the tablet, probably shaving only a few pounds off my travel weight. I decided to go all the way to the light side and see if I could travel with just a smartphone. Call it extreme mobility.

Roughly a year after Verizon Wireless established LTE-based 4G mobile phone and data service in New York City, AT&T's rival LTE network is up and running here and in several other cities. Although its average speeds lagged behind Verizon's in my tests, AT&T's 4G LTE service has a lot going for it.

That's because in a few spots the AT&T network wasn't just fast, it was blazingly fast, with a peak throughput of over 40Mbps. More details on the strengths and weaknesses of each network later. First, let's take a look at the technology.

Buried inside many of the latest smartphones is a capability that few people take advantage of. A feature called tethering lets a phone go beyond talk, email and Web surfing to act as a mobile hotspot that can supply Web access to nearby computers, tablets and other devices.

"It lets [smartphone users] always have the Web with them without taking any extra equipment along," says Allen Nogee, research director for wireless technology at market intelligence firm In-Stat.

To most users, the iPad is a sleek tablet for watching videos, nosing around the Web and reading the occasional e-book. But to tech enthusiasts, the iPad can also be a platform to satisfy their intense curiosity.

We've gathered a bunch of unique gizmos that have one thing in common: they can take the iPad into new -- and often unexpected -- directions.

It's been nearly two years since Windows 7 was released, and yet there are still some features that Windows 7 users may not be taking full advantage of -- such as desktop gadgets. Similar to the Mac's Dashboard Widgets, Windows desktop gadgets are mini-applications that reside on your desktop and can display live data, perform simple functions like search or password generation, or give you a sneak peek inside the inner workings of your PC.

Each new Windows 7 system ships with a handful of gadgets that show dynamic data such as the time, the weather and current news headlines, but there are more than 5,000 gadgets available that run the gamut from the frivolous to the essential. A few come from Microsoft, but the vast majority were written by third-party developers, and most work with both Windows 7 and Vista. All are available for download at Microsoft's Windows Live Gallery.

Because of its association with the BlackBerry brand, Research in Motion's BlackBerry PlayBook will appeal to businesspeople, but on arrival it lacks many corporate must-haves, such as email and 3G wireless data. In fact, it feels like it was rushed to market.

The PlayBook's rubberized surface has a silky feel to it; I prefer it to the naked plastic or aluminum that most tablets use. However, at 5.1 x 7.6 x 0.4 in. and weighing 15 oz., the device feels chunky for a 7-in. tablet -- it's thinner but 2 oz. heavier than the 7-in. Samsung Galaxy Tab.

While tablets such as Apple's iPad and Motorola's Android-based Xoom are continuing to attract popular attention, there are many workplaces that are still based around Microsoft Windows. Unfortunately, Windows 7 isn't really optimized for use in tablets, and it looks like the next version won't be out for another year. So what can people who want to use Windows on a tablet do?

ViewSonic is hoping to offer businesses a steppingstone with its ViewPad 10 dual-OS tablet. Equipped with both Windows 7 and Android 1.6, it gives companies the flexibility to continue using their existing Windows corporate programs while offering access to Android apps.

A headset can do more than keep your hands on the wheel while you're on the phone. It can free you to take notes while talking with a client, sip coffee during a conference call or even doodle while waiting on hold. In other words, a headset today is essential equipment for anyone who spends a lot of time talking on a mobile phone.

Also, it's the law. Eight U.S. states have laws against driving with a phone in your hand, while 30 ban texting behind the wheel. In other words, if you pick up a phone while driving, you're not only doing something dangerous, but risking a hefty fine.

In the business world today, you're judged as much by the technology you carry as by the cut of your clothes. You'll impress no one by walking into a meeting with a clunky old-school laptop.

That's where super-slim "executive-class" notebooks come in. Once the domain of sleek but underpowered devices, this group now includes machines that add a healthy dose of substance to their style.

Last month, I pitted Sprint's WiMax-based fourth-generation (4G) network against its third-generation (3G) network in a series of real-world tests around the New York metropolitan area. My goal was to find out whether the speed boost you'll get is worth the hassle and expense of upgrading from 3G to 4G.

My conclusion? Absolutely - if it's available in your area.