With so many new laptop computers coming on the market, manufacturers trying to distinguish their products have done everything but paint their PCs shocking pink. No! Wait! This just in! Here's word that Sharp has introduced a notebook-sized word processor computer called the "With Me" that comes in either ordinary PC gray or bright pink.

Well, if it's pink you want, the "With Me" may be your choice. Other than that, though, how is a computer shopper supposed to differentiate among the dozens of similar-looking, similarly priced, similarly equipped laptop computers now on the market? What should you look for when you choose a laptop?

If you're going to choose a laptop computer, it's important first to settle on what that generic term means. Roughly, the terms "laptop" and "notebook," pretty much interchangeable now, refer to a full-powered, full-keyboard personal computer that is roughly the dimensions of a loose-leaf notebook, weighs seven to nine pounds with a battery attached and runs all DOS programs. The key test is that this machine should fit in your briefcase, just as a notebook or magazine would.

Anything bigger than this falls into the category of "portable" computer. The portable is pretty much a dinosaur these days, because many laptops match "portable" machines feature for feature.

There are computers smaller than laptop size, but that's where the law of diminishing returns kicks in. The so-called "vest-pocket" or "palm-top" PCs are too small for regular use. You can't type on the tiny keyboards, and the screen is so small it's hard to see. For special uses -- walking around a warehouse taking inventory -- a palm-top may be acceptable. But if you need a real computer, you can't go any smaller than the laptop level.

There are certain objective measures that a laptop computer should meet before you buy it.

Be sure to get a computer with a hard disk. The penalty in weight and price is not enormous these days, and the gain -- no need to haul floppy disks wherever you go -- is important. Some laptops come with one or two megabytes of random access memory (RAM) configured to work like a disk, but that solution is not successful. Eventually, you will need more space than that RAM "disk" provides to store programs and data. Because it's much more expensive to buy a third-party hard disk and install it in your laptop later, get the internal hard disk built-in when you first buy your PC.

There are several points to look for in laptop batteries. You should demand about three hours' operating time on a single battery. Some PCs get more, which is fine, but you needn't take anything less. The battery should be light enough (say, two pounds) and small enough that you can fit a second one inside your briefcase along with the computer.

The battery charger transformer units that various laptop makers provide vary significantly. You want a unit that will recharge the battery from empty to full in the span of one night's sleep. That way, you can start every day of a business trip with a fully charged battery. Some laptops take 12 hours or more to fully recharge. Avoid them.

Unlike desktop computers, some laptops still come without the full complement of "ports," or connecting plugs, on the back. You need a printer ("parallel") and a modem ("serial") port, another to access an external floppy-disk drive, and a connector to hook up an external display screen, so you can use your full-sized color monitor at home. A mouse port is useful if you plan to run Microsoft Windows on your portable.

Some laptops come with beautiful display screens nowadays, but beauty is in the eye of the buyer. You should look at several systems before you choose. The standard system now is a dark-blue-on-light-blue EGA monochrome monitor, quite acceptable for text work. The so-called "page white," or black-on-off-white, screens on the newest Zenith laptops are fantastically sharp and display graphics remarkably well.

Unless you have some unusual need, don't get a color laptop. The color liquid-crystal displays available for laptops now are not worth the $3,000 they add to the unit's cost. We saw the latest color liquid crystal display screens recently at the Tokyo computer show. They're far ahead of what was available just a year ago, but they're still not as good as an ordinary desktop VGA color system.

Finally, don't let a salesman talk you into the built-in modems that come with laptops. In our experience, these things have an amazing failure rate. Instead, buy one of the tiny cigarette-pack modems from Everex or WorldPort. They're cheap, reliable and easy to hook up. In fact, with the money you save by not getting the internal modem on your new laptop, you can probably buy the WorldFax modem. It's the size of a cigarette pack and has a facsimile machine built in.