Competition in the personal computer industry is most furious in the lap-top market. More than a dozen new models have hit stores in the past year, and more are on the way.

The industry believes this market will soon be huge, and with good reason. Not only do lap tops let people take their PCs wherever they go and work with them on the fly, they also clear desk space back in the office. The growing use of the smaller 3 1/2-inch disk drives on desk-top machines has helped acceptance of lap tops, nearly all of which use the smaller drives.

Nearly all of the new lap tops are designed to run software written to the IBM PC standard. But IBM's entry in the lap-top market, the PC convertible, is now in its third rendering as IBM, far from setting the market standard, scrambles to keep up.

The past year has seen dramatic improvements in the LCD screens used with most lap tops, resulting from what is called "supertwist" technology. The original portable PCs, which someone correctly dubbed "luggables" because they weighed 30 pounds, are fast giving way to sleek machines that weigh half that, or less, and will run on battery power for up to eight hours.

No one has yet produced a lap top that is clearly the best -- the lightest, fastest and most powerful, and with the best keyboard, sharpest screen and most storage. But there are some clear winners in different categories. The envelopes, please: For Most Power In The Smallest Package: the Toshiba T-1000. At 6.4 pounds, it is three pounds under the next lightest machine, Toshiba's T-1100 Plus. But the T-1000 has only one disk drive (a 720K, 3 1/2-inch floppy), a small screen and a slow processor. Good price, though: it lists for $1,199.

Best Screen: the Zenith Z-181 and Z-183. Sharp blue characters on a white background in a screen that is as large as that of some desk-top monitors. The Z-181 has two 3 1/2-inch floppy drives, a two-speed processor, and weighs 12.5 pounds. The Z-183 has one 3 1/2-inch floppy drive and one 10-megabyte hard disk. The Z-183 is larger overall, with a more expansive keyboard, and weighs 15.5 pounds.

List price: $2,399 for the 181, $3,499 for the 183. But if the screen on the newly announced Kaypro 2000+ is as good as the photograph of it that the company is sending around, it will overtake the Zeniths. The Kaypro+ is expected to list for $2,795.

Most Power: the Toshiba 3100. This is the only lap top that uses the Intel 80286 processor. The rest use the less powerful and slower Intel 8088 or 8086 (or NEC's equivalent chips). The 3100 barely fits into the lap-top class. It weighs nearly 15 pounds and does not run on batteries. But its gas-plasma screen is bright and sharp (if you like reddish orange on black) and it comes with a 20-megabyte hard disk. It also comes with a list price of $4,699.

Most Power For The Money: the Datavue Spark. For a list price of $995, you get a 384K portable with a good LCD screen and one 3 1/2-inch disk drive. Another $300 upgrades you to a two-drive system with 640K. With a dual-speed NEC V-20 processor, the Spark will run at twice the speed of the original IBM PC. (The street price of the Spark and its list price seem to be the same. Most other lap tops can be had for hundreds of dollars less than their list price.)

Best Overall Value: the NEC Multispeed. The NEC has a good supertwist screen, and the recently announced backlit version looks even better. It has the fastest processor of all except the Toshiba 3100, two disk drives, a nice keyboard with function keys at the left, and a separate numeric keypad. It weighs just over 11 pounds and has several programs, including a word processor and data base, built in. It lists for $2,195.

Honorable Mention: the Toshiba T1100 plus. It weighs less than 10 pounds and has a good screen, two-speed processor and two disk drives. It lists for $2,095. Also: the 13.5-pound Tandy 1400LT. It has a particularly good screen, two drives, two-speed processor, nice keyboard and lists for $1,599, which is likely to be the street price also.

Note: A modem is a must for a portable PC and, of the computer prices quoted above, only those for the Zenith models include a 1,200-baud internal modem. It is an option costing up to $400 with the others. But there are several tiny new external modems costing $200 or less that might be a better choice. More about them in a future column. :: Brit Hume is a contributor to the Washington Post Writers Group. Hume is an ABC Capitol Hill correspondent and the founding editor of a computer newsletter.