Measuring 0.8 inches thick and sporting a starting weight of 4 pounds, the T400s is one of the lighter all-purpose laptops around. It makes the old T400 (at 1.5 inches thick and around 6.5 pounds) look downright big-boned. What's even more impressive is that the T400s still manages to squeeze in a lot of the extras that Business Users require. This model is literally lined with ports. Whether it's the five-in-one flash card reader or the space allotted for a 9.5mm DVD-ROM burner (or Blu-ray option), this machine has you covered. It even has stuff that might seem like overkill, such as VGA and a DisplayPort option, but even that gives you the opportunity to plug in two monitors. I'm personally a big fan of the built-in USB/eSATA port, which is perfect for high-speed data jockeys. (What I'd love to see in the next iteration is more than one pass-through USB charge port for powering USB devices while the laptop is off; for anyone with too many gadgets and power supplies, this feature is incredibly handy.)

The ThinkPad T400s earned a sound mark of 112 in our WorldBench 6 test suite, smoking the trim Acer TravelMate 6293 (and many of the other all-purpose laptops in our Top 10, for that matter) and coming in about 20 points faster than the T400. Applications loaded swiftly on the 128GB SSD Hard Drive, which uses an Intel Core 2 Duo SP9600 processor with 2GB of RAM. To help cut down the size of the system, however, the company dropped the discrete graphics card. That downshift to Intel's integrated graphics will prevent you from using the T400s for games. But this is a business box, after all.

The nine-cell battery that gave the T400 its incredible longevity is gone. Our test unit came with a six-cell battery as standard, with no word of larger batteries on the way. As a result, this laptop managed to survive only 5 hours in our battery tests. Not a horrible result, just something to keep in mind when you're preparing for your next cross-country flight.

Showing off a bright 1440 by 900 pixels, the 14.1-inch, LED-backlit screen is an eye-catcher indoors and out. Like the T400, the T400s uses a matte coating, as opposed to a flashy, glossy surface that looks good only indoors. Examining the two side by side, I found that the T400s's screen was sharper; sky blues, for example, popped more and looked richer on the T400s. One mechanical quirk I noticed, though, is that the hinge of the T400s is a little loosey-goosey. If you're sitting at a desk, that's not much of a problem--but if you encounter any turbulence midflight, the screen can flop back.

The keyboard is typical Lenovo fare--excellent. But that doesn't mean Lenovo coasted. For instance, two of the keys I use a little more often that I should admit--Esc and Del--doubled in size. The designers also managed to retain all the buttons from the larger, thicker T400 and still make room for a handy microphone-mute button (more on that in a minute).

The trademark ThinkPad pointer nub is present in addition to a touchpad. Having both options is nice, but the dual sets of pointer buttons can result in accidental presses if you're not familiar with the layout. That said, a tip of the cap to Lenovo: The tiny T400s has a larger, more satisfying textured touchpad compared with its big brother.

Wireless gets a major upgrade. Beyond the standard 802.11b/g/n Wireless LAN (and optional Bluetooth), you get WiMAX3, integrated WWAN, and ultrawideband connectivity options.

Despite all the progressive tech on board, in a laptop of this size some shrinkage was inevitable. Gone is the PC Card slot (a 34mm ExpressCard remains). Say so long to FireWire. And the headphone/microphone jacks merged into a single plug. That's a thoughtful design decision for the perpetually mobile, as you can plug in your wired cell phone headset (from, say, an iPhone or a Palm Pre) and it'll work just fine.

Speaking of...well...speaking, the T400s has been tweaked with Web chats in mind, and I'm not talking only about the built-in Webcam. The tiny, tinny speakers of the T400 got a boost--the speakers of the T400s are better in just about every sense. The sound, while far from perfect, is a marked improvement over audio from the average laptop. And it can reach a reasonably high volume--perfect for when you want to talk to your coworkers back at the office via Skype. The microphone-jack mute button, parked just above the keyboard, is convenient for those times when you want to give the silent treatment.

Then there's the software that business users have come to know and love: the ThinkVantage application suite. Common tasks such as setting up wireless connections and managing power-consumption settings are readily available, and power users will appreciate being able to back up data or configure security settings on the fly. The ThinkVantage suite largely serves as a front end for functions that Windows can handle, but it does a lot to improve overall user efficiency.

Some advanced features, like the Active Protection System, may escape most users' attention altogether. The laptop's shock-mounted hard drive is designed to protect your data from damage if you're working in especially turbulent conditions. You'll find that most useful if you're prone to dropping expensive hardware; but even if you're the careful sort, it's a well-conceived feature that prevents the hard drive from spinning when it detects an excessive amount of vibration. The system adapts to your usage patterns and ignores steady, persistent vibrations, such as when you're working in a car or on a bumpy express train.

Starting at $1599, the Lenovo Thinkpad T400s can be a compelling little laptop. Of course, once you start adding all the bells and whistles, the price kicks up significantly (our model, as reviewed, sells for $2130). Still, thanks to sturdy construction and great performance packed inside a slim profile, the T400s is a winner, and great for the jet-setter who wants a little more out of their mobile machine.