(MONEY Magazine) – All-in-one desktop PCs are hot, in part because computer makers are hoping the hip, space-saving designs will spur buying. The fire was fueled early this year when Apple unveiled its first-ever flat-panel iMac. Then in August, Gateway refreshed the Profile, upgrading it from a less than stellar performer into a high-powered machine. The two companies must be on the right track--electronics giant Sony just introduced its own entry, the Vaio PCV-W10.

Apple reintroduced the integrated monitor and PC concept in 1998 with its hugely successful Blueberry iMac. But its shape was essentially that of a traditional CRT monitor, so it took up a fair amount of space on the desktop. In late 1999, Gateway brought out the Profile. With its liquid crystal display, the Profile was sleeker than the iMac, but it was really just a watered-down laptop with components crammed into the monitor and base. It had two PC card slots, but the maximum amount of RAM it could hold was a paltry 256MB. The Profile was, in a word, underwhelming.

In fact, the two biggest knocks against previous all-in-ones were that they were not expandable and they came with second-rate components. But today's models are tricked out with loads of RAM and massive hard drives as well as very good video and sound cards, so expansion is not really an issue. I tested three currently available all-in-ones. While they're not for power users who like to break open their machines and upgrade internal components, they do provide enough juice for most folks--and they do so with a certain amount of style.

Apple 17-inch flat-panel iMac ($1,999). Its hemispherical base isn't small--10.6 inches in diameter--but the iMac's crisp 17-inch, wide-screen, flat-panel digital display rests on an adjustable arm that makes it seem to float above your desk. The result is a smaller footprint than the original iMac. The 17-inch model comes with a SuperDrive that burns both DVDs and CDs. Paired with iMovie and iTunes, it's ideal for moviemakers who want to share their masterpieces, and for music fanatics who mix and burn their own CDs.

Even better, this iMac runs the recently introduced Jaguar, OS X Version 10.2. While I like Windows XP, Jaguar is the best consumer operating system I have ever used. Then there are the applications that are specifically designed for Jaguar and that come with it, like iChat (one of the few programs compatible with AOL Instant Messenger), iCal, iPhoto and iDVD. To put it simply: iLike.

That's not to say the iMac is perfect. Apple relies on Motorola's PowerPC microprocessor, which tops out at 1.25GHz vs. nearly 3GHz for Intel's chips. I know you can't accurately compare speed through megahertz alone, but the fact is that the iMac is a bit slower than its Intel-powered rivals. (Our test model's 800MHz G4 booted up far more slowly than the Profile, for example.) The new iMac also comes with 256MB of conventional RAM (expandable to 1GB), but at this price, it really should have 512MB of DDR RAM (double data rate RAM), which comes on Apple's professional line of desktops and allows you to access data faster. And in a computer designed for multimedia, an 80GB hard drive is probably not enough. You may need a FireWire external drive sooner than you think.

That said, the new iMac is a beautiful thing. Paired with Jaguar, it really does give Windows users a compelling reason to make the switch.

Gateway Profile 4XL ($1,999). You've seen the TV ads: A Profile leaps over a line of iMacs, stops and sticks out its disk tray tongue. More telling, however, is the disclaimer at the bottom of the screen, "Base and monitor movements are simulated."

Indeed. Contrary to the commercial, the Profile's screen can be tilted only foward or backward. There's no height adjustment. That's a problem, because the Gateway's designers put the disk tray and floppy drive below the monitor but had to keep them at a height that would allow the keyboard to fit underneath. As a result, the Profile's ample 17-inch LCD sits uncomfortably high--high enough to make the monitor unstable.

In fact, the overall design of this computer is somewhat misguided. the Profile comes with a power brick as big as an external CD-RW drive. No matter where you put it, it's bound to be in the way. This Profile costs the same as the iMac but only comes with a DVD-ROM/CD-RW drive. You can watch, but not burn, DVDs. The Profile also has an analog monitor, and the difference in clarity is obvious, particularly when the iMac and Profile are viewed side by side.

None of which is to say that the Profile is a bad machine. Its 2.66GHz processor speed is substantial, as are its 512MB of DDR RAM (expandable to 1GB) and 120GB hard drive. The machine also has two FireWire ports and a PC card slot. That's useful, particularly if you want to do video editing or if you decide at some point to go wireless.

Compared with the iMac, the Profile falls short. But if you want an all-in-one PC and would die without Windows, by all means, go Gateway.

The Sony Vaio PCV-W10 ($1,600). The newest entry in the all-in-one market, from Sony, is known as the W--a designation I am assured has nothing to do with our current President. Unlike the iMac and the Profile, the W is not designed to do all things well. Instead, it's intended for light multimedia use.

The svelte silver W comes with a 15.3-inch-wide screen that's perfect for viewing DVDs. Flip up the keyboard and it takes on the look of an expensive Bang & Olufsen stereo component--audio track info is displayed in the screen space just above. You can use it to edit digital video; although the Celeron processor is not ideal for such a power-hungry task, it provides enough juice for the occasional auteur.

The W isn't going to satisfy gamers or people who regularly use power-hungry applications, and it doesn't burn DVDs. But the W does have 256MB of DDR RAM (expandable to 1GB), a 60GB hard drive and two PC card slots. And it carries enough of the cool factor that I'd put one in my living room just so everyone would talk about it.