"Peace on Earth, good will to men" isn't trendy anymore, says Hallmark Cards, the world's largest Christmas card manufacturer. Out of 2,425 designs, only three Christmas cards have the word "peace" on their covers, a check by the company's computer shows.

"Cards reflect what's going on in society," explained Hallmark spokeswoman Nancy Matheny, adding a chilling thought: "Peace as a theme doesn't have the same impact this year as it did in the 1960s and 1970s. Then the peace movement was strong and so were cards with peace motifs. This year, some cards do say 'Peace on Earth' on the inside, but we have only nine dove covers and two lamb and lion covers out of the 2,425 different cards. Now peace symbols just aren't popular as a cover design."

Instead, high tech is making a byte with cards that play songs, make rude noises or smell like a pine tree.

The peace angel seems to be having a hard time making a landing, in a year when robots are on the march, the defense budget is bigger than Santa's and rumors of "star wars" are rife in the land.

* Santa Claus, the children will be happy to hear, with Rudolph the radar reindeer, has landed safely on many cards. It's a slimmer Santa, thanks to his being portrayed as jogging and working out on many of the cards.

* Instead of world wishes, cards this year are retreating into the haven of home. President and Mrs. Reagan are part of the trend, with their Jamie Wyeth card showing an American flag flying above a snowy White House silhouetted against a pink sky.

* "Glory to God in the highest," thank heaven, is still around -- religious cards account for a third of sales.$ Tops in Tech

For those who want to send the very verse, the "Computer Poet" will find the rhyme. Computer Poet Corp., in Incline Village, Nev., uses an Apple Macintosh computer. The software program asks these questions: number of persons you're writing; name(s); occasion (Merry Christmas, Happy Hanukah, You owe me money, Happy divorce, I blame you, I'm angry, Let's go out, I lost my shirt); residence; principal traits (cheapskate, loves to eat, beautiful and sexy); type of love extended (child, adult, relative); and name of sender. The machine writes a rhyme (allegedly with 140 million possible variations) to the intended recipient. If you like it, you push "print" and pay $3. If you don't, you push "erase" and start all over. If you still don't like their version, you can -- imagine that -- write your own. The price includes an illustrated cover for your message. At its Connecticut Avenue store, Jacobs Gardner, an office supply company, has one of 200 devices in the country.

No more silent night -- except for the carol -- with today's cards. Hallmark has figured out a way to keep the music coming -- the firm claims it's a tiny integrated circuit, but you and I know it's really a minute music box. Choose either "Deck the Halls" or "Silent Night."

American Greetings goes further than Hallmark by concealing an itty-bitty sports car inside the card. It reads: "I wanted to get you something really special for Christmas -- how does a brand new sports car sound?" When you open it up, you hear a noise like the one from a sports car's exhaust pipe. The other American Greetings "special effect card" apparently has the sounds of Santa himself captured inside the card. He shouts "Rah! Rah! Rah! Sis! Boom! Bah! Yea! Christmas! Ho! Ho! Ho!" Bert Hobrath of American Greetings claims it's all done with a microchip and a battery, good for 1,500 plays. Finding Peace

Some peace cards can be negotiated. UNICEF this year has only one true peace symbol card -- a handsome embossed dove with olive branch by Howard S. Alstad of Canada. A card that says "peace" in more than a dozen languages comes from a '70s-type source -- the San Diego Draft Resisters Defense Fund.

Peace cards are still popular in the rarefied atmosphere of the hand-press art publishers. Ted Naos, a Catholic University architecture professor, and his wife Barbara (with the help of a staff of eight) hand-made 500,000 die-cut cards in 20 designs on two presses in their Baltimore studio. That's up 25 percent over last year for the family operation. Reassuringly, Naos said a cutout card reading "Peace on Earth" ornamented with stars and doves is selling exceptionally well this year, even better than last year's "Peace."

The National Gallery of Art, a great source for Christmas cards reproducing artwork, offers more hope for the future from the past: an American weathervane angel and the Rembrandt van Rijn "Angel Appearing Unto the Shepherds," both bearing "Peace on Earth" messages, and two "Peaceable Kingdom" cards by American painter Edward Hicks.

Fitness was in favor in the last century, as the Library of Congress illustrates with a "Christmas Cracker" post card from 1886 that bears the quotation from Pliny: "Simple diet is best, for many dishes bring many diseases, and rich sauces are worse than even heaping several meats upon each other."

If you're too late for Hanukah, which began Tuesday night at sundown, you can be early for Passover, with the Library's gorgeous page from the Washington Haggadah, an illuminated Hebrew manuscript on vellum for the Passover Seder, dated Jan. 29, 1478.

As for the traditional home card, possibly the prettiest are the photographs of doll houses, including one interior, published by Flora Gill Jacobs' Washington Dolls' House & Toy Museum.

In keeping with this year's lack of peace themes (and not too much humor), there's Hallmark's LITE card ("A third less serious than regular greeting cards"). Inspired by Nancy Reagan's 1983 Christmas guest (Mr. T), it shows a belligerent Santa hung with gold necklaces and bracelets and wearing brass knuckles. The legend says: "I pity the fool that doesn't believe in Mr. C."