OULDN'T it be cool if you could buy stock in absolutely anything? "The broader celebrity market was up, buoyed by a rise in shares of TV war journalists and Nicole Kidman," you'd hear on the radio. "Public smoking is down another two points today, doggie raincoats are up an eighth and mindless pursuit of wealth continues its decline to close at $1.24. And in a twist, the stock market as an investment concept hit an all-time low of 43 cents a share in late-afternoon trading."

In that world, one investment strategy would be to put your money in cellphones with built-in cameras; nearly two million of them are expected to fly off American shelves this year, and they show enormous promise. Of all the combination gadgets that have come and gone, this is one that makes sense - after all, cameras and cellphones are both gizmos that don't do you much good unless you carry them at all times.

In the earliest days of cellcams (that is, six months ago), the lens was a snap-on piece that begged to get broken off, left behind or lost in your battery drawer. But no more. The new Nokia 3650 (from T-Mobile or AT&T Wireless), Panasonic GU87 (AT&T Wireless), Samsung V205 (T-Mobile) and Sanyo 5300 ( Sprint PCS) are no larger than the sleek, silvery, status-conscious cellphones they replace - but each has a built-in lens and shutter button for photos on the fly.

Before you read on, however, an expectation-setting moment is in order. When it comes to resolution and quality, no cellcam can replace a "real" digital camera.

The best resolution you can get in a phone is 640 by 480 pixels (on the Sanyo and Nokia), not even enough dots for a 4-by-6-inch print. At the other extreme, the Panasonic's 132-by-176-pixel photos are so tiny, they're appropriate only for sending to other phones' screens and attaching to e-mail messages. It makes you the proud owner of a .02-megapixel digital camera.

Even so, a cellcam is just about the most satisfying piece of pocket paraphernalia since the bifold wallet. Resolution isn't everything; just ask the patrons of 50,000 mall photo booths. Being able to snap a photo and send it instantly is invaluable when you're shopping and want your spouse's opinion on a certain house, antique or puppy; it's a form of telepresence for insurance companies and newly minted grandparents; it even offers a shot at capturing historic moments to sell to the evening news.

But forget about utility. As cellcams have shown in Japan, where they're a hypersonic hit, the bigger selling point is the fun factor. It's just a blast snapping little bits of your life, sights and scenes and faces and friends, and firing them off to other people. The Panasonic and Sanyo even let you assign a mug shot to each person in your phone book, so that you can literally see who's calling.

Don't expect to get one of these phones free when you sign up for cell service. All of them are top-of-the-line phones with top-of-the-line prices. They offer big, bright color screens; features like caller ID, conference calling and speed dialing; crude, very slow access to e-mail and the Web; phone-to-phone text messaging; about four hours of talk time; and a built-in calendar-travel alarm. All but the Samsung let you dial by voice ("Call Chris") - an indispensable feature if you drive. And all but the Nokia offer a secondary, outside screen that shows you who's calling before you even open the clamshell. (The light on the Panasonic's lid even illuminates in bright blue, green or orange depending on the caller's social importance, assuming you've taken a moment to color-code your phonebook.)

To take a picture, you press a Camera button (Samsung, Sanyo) or choose Camera from the main menu (Nokia, Panasonic). The phone's color screen becomes a viewfinder. When you like what you see, you press a shutter button to snap the shot.

At this point, you can file the photo on the phone or send it by e-mail. You can also send it to another cellphone - sort of; the recipient must subscribe to the same cell carrier and use a compatible color-screen phone.

The biggest difference in design among these phones is their approach to self-portraits: if the lens is on the cover of the clamshell, and the screen is on the inside, how can you frame a photograph of, say, you and a friend?

On the slab-style Nokia phone, you can't. The lens is on one side, the screen on the other. End of story.

Panasonic addressed the problem with a dime-size convex mirror on the lid, just under the lens. It's a cost-saving cop-out, but at least you can tell when you're centered.

On the Samsung, the lens is on the rotating barrel of the phone's hinge. You can turn it to any angle you like - up, down, toward you or away - without taking your eyes off the screen.

Sprint's Sanyo phone, on the other hand, has two color screens: the big one inside and a one-incher outside. That secondary screen is not only handy for framing self-portraits, but it also shows a caller's photo when the phone rings without your having to open the clamshell.

The Sanyo ($350 after rebate) is also the only phone with a built-in flash. Now, you don't exactly have to worry that the flash might blind passing aircraft; it has only a 30-inch range. Still, even a feeble flash can help low-light or backlighted portraits of the type you're likely to take with a cellphone. That feature, along with the 640-by-480-pixel picture size and the self-portrait screen, makes the Sanyo the best digital camera that ever phoned home.

Even if it's the best camera, though, the Sanyo has its drawbacks as a phone. At about 1.3 inches thick, it's porkier than its rivals. Its software needs refinement, too. For example, e-mail and text messages don't wrap to fit the screen. You're reduced to the ridiculous exercise of having to scroll horizontally and vertically just to read, "Running 15 min late - start without me." And Sprint makes you do your e-mail work via a Web site, a clumsy solution with all the speed of an anesthetized slug.

Actually, you can find examples of design silliness on most of these phones. On the biggish Nokia 3650, for example, the dialing keys are arranged in, of all things, a circle. All right, we get it: it's supposed to be some kind of neo-retro-post-modern homage to old rotary phones. Very cute. But trying to tap out text messages, or even dial a phone number by touch, is pure hell.

That's too bad, really, because the Nokia is otherwise a very powerful phone (and, at as little as $150 after rebate, a relatively inexpensive one). It's a serious organizer, capable of running add-on programs; it can, surprisingly, record tiny 10-second videos (with sound, if you use the T-Mobile version); and it's the only phone whose memory you can expand to hold more pictures (by inserting a Multimedia Memory Card).

The Samsung v205 ($350 after rebate) is the smallest, lightest phone of all and offers truly spectacular-sounding ringer tones; but you have to wonder if its designers inhaled a bit too much of that new-phone smell. The software offers menus that only Mr. Rubik could love. Worse, the center button of this phone's four-way rocker switch is not the Select button, as it is on its rivals; it's the Go to the Web button. The actual Select button, the one you need roughly 165,000 times more often, is parked off to the left, in cellphone Siberia.

The only phone completely free from screaming design deficiencies is the Panasonic GU87 ($300 after rebate). It's thin and beautiful, and its crisp, well-oiled closing mechanism could have come from the Lexus car-door division. The pictures are very small, but they have better color fidelity and contrast than those on this phone's rivals. Meanwhile, the Panasonic offers thoughtfully designed and (for a cellphone) simple software.

Incidentally, you'll get the prices mentioned here only when you sign up for a new account. If you're already an AT&T Wireless customer, for example, the price you'll pay for that Panasonic depends on your existing plan, how long you've been a customer, and, no doubt, how friendly you are at the phone store.

And speaking of ambiguity, note that you'll pay $3 to $20 more per month (on top of your regular voice plan) for the privilege of sending photos and other data wirelessly, depending on how much you intend to send. For example, T-Mobile's $3 monthly plan lets you send or receive 1 megabyte of information, which the company says is enough to handle 30 incoming or outgoing photos.

So shop according to the emphasis you prefer: the Sanyo as a camera-cellphone, the Panasonic as a cellphone-camera. In this world, you can't buy stock in people or concepts. But there's nothing to stop you from investing in a little fun.