Most of the major specs I recommended two weeks ago in my annual spring guide to buying a computer hold true for laptops as well as desktops. That guide can be found at walt.allthingsd.com/guide. But buying a portable involves additional factors, so here are some tips for making laptop purchases.

First, you may want to wait to get that new laptop until later this year or early in 2008. There are a number of interesting new hardware features coming. One is called a “solid-state drive,” or SSD, which replaces the traditional hard disk with a faster drive made of memory chips like those used in digital cameras. Another is a “hybrid hard drive,” or HHD, which combines memory chips with a standard hard disk, for faster start-ups.

Also, more and more laptops will be using light-emitting diodes, or LEDs, to light up their screens — a method that promises to be both brighter and less power-hungry.

You also may want to wait for laptops with a new type of Wi-Fi wireless networking built-in. It’s called “N,” and promises to be faster and to have longer range.

For Windows Vista users, another new laptop feature coming soon is a small screen on the lid called a SideShow, which can display calendar appointments and new emails.

Even if you don’t wait, there are some features to know about that aren’t available on most desktops. One is a built-in Web camera and microphone, highly useful for making video calls and recording videos to be posted online. Another is a feature that allows you to play music, videos or DVDs without booting up Windows.

In addition, if you travel a lot, you may want something called a built-in WWAN, or Wireless Wide Area Network. This is essentially a cellphone modem that makes Internet connections over a cellular carrier.

Another key feature is a new kind of slot on the side of most laptops for add-on cards, like wireless modems. It’s called an ExpressCard slot and, confusingly, it comes in two sizes. Your old-style cards, called PC Cards, won’t fit in these new slots, so unless you want to buy new cards, you might look for a laptop that has both the old and new slots.

Battery life, weight and size remain crucial on laptops, unless you are buying a huge “desktop replacement” laptop, which will rarely leave the house or be unplugged. For everyone else, I recommend finding a laptop that offers at least three hours of battery life on a single charge, without requiring you to dim the screen so much you can’t see anything.

Most laptops cluster around the six-to-seven-pound range, which is fine for occasional travel, or for carrying between classes, or between home and office. But if you are a frequent air traveler and have the budget, shoot for a laptop that weighs four pounds or less and is small enough to use on a seat tray in coach even when the person in front of you reclines.

The most expensive laptops are at the extremes–huge, multimedia machines and ultra-portable models for hard-core road warriors. Most well-configured Windows laptops, with typical 15.4-inch screens, are between $900 and $1,500.

I find that laptops with 13.3-inch widescreen displays make a nice compromise between mobility and power. At the moment, there are very few brand-name models in that size, notably Apple’s $1,099 MacBook, which weighs 5.2 pounds; and Sony’s Vaio SZ line, which weighs 4.1 pounds but costs roughly twice as much. More 13.3-inch models are coming later this year from other manufacturers.

Finally, there’s the perennial issue of Windows versus Mac. Apple’s two laptop lines, the MacBook and MacBook Pro, are very good. They have better built-in software than any Windows laptop I’ve seen and don’t suffer from the security issues that plague Windows. And they can even run Windows software, if you need that.

But the Mac laptops lack some features that are common on Windows portables, such as slots for camera memory cards and built-in cellular modems. And the MacBook even lacks an ExpressCard or PC Card slot.

Among Windows machines, I think Sony and Lenovo make especially well-designed laptops, but almost any name brand would be fine.

Addendum: I’m happy to say there is a new, expanded and redesigned online home for all my columns. It’s at walt.allthingsd.com and access is free. It contains the current versions of the columns with the accompanying videos, plus a searchable two-year column archive and a new blog called Mossblog, which I will update occasionally.

This new column home page is part of a larger new Web site called All Things Digital, at allthingsd.com. In addition to my columns and blog, it contains technology news, analysis and opinion from journalists Kara Swisher, Katherine Boehret and John Paczkowski, and guest blogs from prominent technology figures.

My columns will still be published on The Journal’s main Web site, WSJ.com, which is available to paid subscribers and includes a much larger archive, going back more than a decade.

• Email me at mossberg@wsj.com

And the cellular broadband services, such as Verizon Wireless’s BroadbandAccess, can operate at speeds roughly equivalent to, and sometimes well beyond, the speed of basic wired home DSL service. That means you can surf the Web, and get email and large attachments pretty efficiently.

The card for the Verizon network

A small percentage of users hook up to these cellular broadband networks using laptops that have the necessary gear built in. Another small group uses a cellphone as a modem. But most users of these networks use external cellular-modem cards that plug into a standard slot on the side of their laptops. Therein lies a problem.

The computer industry is in the process of dumping that standard slot, called a PC Card slot, for a new, incompatible slot called ExpressCard. So, buyers of many new laptops are finding their cellphone modems are obsolete.

Now, Novatel, a leading maker of these cards, has come out with a couple of new ExpressCard versions for cellular broadband networks. One, which works on Verizon Wireless’s network, is already on the market, sold by Verizon and by Dell. The second, which works on Cingular’s BroadbandConnect high-speed network, will go on sale from Dell and possibly Cingular later this year, likely late November.

I have been testing the Verizon version of the card, called the V640, as well as a pre-release model of the version that works with Cingular, which Novatel calls the Merlin XU870. The tests not only gave me a chance to evaluate the cards themselves, but also to compare the Verizon and Cingular high-speed networks.

My verdict: The cards were easy to set up and use, and worked well. But the two high-speed networks are very different. While Cingular gave me higher speeds than Verizon in a couple of locations, the Verizon Wireless BroadbandAccess network crushed Cingular’s BroadbandConnect in most places I compared them.

This wasn’t a rigorous scientific test. I used two different laptops, an Apple MacBook Pro and a Dell Latitude D820. The Cingular tests were all conducted on the Dell, because the Mac software for the Cingular card won’t be ready until the card goes on sale. The Verizon tests were all conducted on the Mac. On both machines, I used the test service at speakeasy.net, accessed via the Firefox Web browser.

Also, I tested the cards in only Washington and New York City, and on Amtrak’s Acela Express trains in between. That is a heavily populated region; it’s also Verizon’s home territory, and Cingular might have done better in other parts of the country. Verizon has been rolling out its high-speed network since 2003; Cingular is well behind. Verizon offers the service in 185 metro areas; Cingular is in just 75.

Both cellphone carriers charge $60 a month for unlimited data service using the cards, if you have a voice plan with them. The new Verizon card costs $180. The new Cingular-compatible card is likely to cost $50 more.

The cards look nearly identical, and each works on both Windows and Macintosh computers. On Windows, you must connect using special software. On the Mac, you can simply use integrated software from Apple, if you choose. Both cards have small flip-up antennas and indicator lights. Both worked fine.

Verizon’s high-speed service is often called EVDO, for its underlying technology. Cingular’s service uses a technology called HSDPA.

In my tests, which involved about 20 head-to-head comparisons, the Verizon card and network averaged 818 kilobits per second “downstream” (to get Web pages, and to receive email and attachments) and 113 kbps “upstream” (to send email and files).

By contrast, the Cingular-compatible card averaged just 463 kbps downstream and 77 kbps upstream. Plus, during the three-hour train trip, Cingular disconnected me, or simply had no coverage at all, eight times. Verizon did so only once. Verizon has a deal with Amtrak that supplies data service inside the trains, which helped, but this in-train signal doesn’t include the high-speed EVDO service.

Cingular did beat Verizon in two places: my hotel in New York’s financial district and my office in downtown Washington. In the hotel, the Cingular service got a downstream speed of 1753 kbps — its highest in my tests — versus 888 kbps for Verizon and just 747 kbps for the hotel’s expensive wired Internet service. In my office, Cingular got 1133 kbps downstream versus 644 kbps for Verizon.

But the downstream speeds varied wildly. In Trenton, N.J., the Cingular service managed just 16 kbps. The best for Verizon was 1366 kbps in New York’s Penn Station, while its worst was 132 kbps between big cities in New Jersey.

I recommend both new cards. But unless you live, work and travel in very strong Cingular coverage areas, Verizon is the better choice for high-speed wireless data, at least today.

Email me at mossberg@wsj.com.