Open Monday through Friday, 11 a.m. to 2 p.m.; Monday through Thursday, 6 to 9:30 p.m.; Sunday, 11 a.m. to 3 p.m. Major credit cards. Reservations.

Food: You can't judge the meal by its cover

Style: Buffet service is a grand hotel dining room

Price: $12.50 at lunch and brunch, $19.50 at dinner

ONCE UPON A TIME a beautiful dining room was born to the Madison Hotel. Named the Montpelier Room, it started with all the advantages - silver, crystal, rosewood paneling. People came from far and wide to pay homage to this beauty swaddled in blue and gold silk and velvets, jeweled with glimmering chandeliers and fine old paintings. Besides homage, they paid a lot of money, but they didn't seem to mind that. After all, the value of hospitalityis beyond price, and the kitchen delivered tempting morsels which did honor to the restaurant's great beauty - or so they did.

As the Montpelier Room matured, however, there were signs of its being a little . . . well . . . spoiled. Pomposity creeping into the table service? Rumors flew of bland sauces and soggy pastries, Jealousy, perhaps?

But now the Montpelier Room is going through a stormy adolescence, and the strain has begun to show. What happened, you see, is that the pampered Montpelier Room came to believe its looks were enough. It didn't need it s waiters. It didn't need its cooked-to-order delicacies. It could carry on as a buffet.

At dinner now the cold table is set with a half-dozen composed meats and seafoods in seas of psychedelic green and orange aspic decorated with squiggles of mayonnaise. Salmon pate and slices of stuffed veal overlap on pedestals of bread frosted with rosettes and swirls. The meats glisten like jewels, having been painted with aspic. But the aspic has no flavor and among the array of appetizers, only the liver pate and gravlax (home-cured salmon) with sweet browm mustard sauce withstand closer scrutiny. A dozen salads - flageolets with pimentos, chicken salad with grapes and diced honeydrew - make a spiffy display but don't stand out in the crowd. The appearance is what impresses, rather than the taste.

As tempting as a buffet can look, and as seductive as such vast choices may be, many dishes - notably main dishes - are sullied by their wait. The table of hot foods is a parade of look-alike silver chafing dishes presided over by a young woman who carves and serves with lightning speed. She slashes through a rib roast to present you with a slice and a drizzle of meat juice (the real thing, none of that diluted factory bouillon). She whisks your warm dinner plate across the parade ground, flicking on a couple of pale veal scallops, too quick for you to notice the twin lines of gristle. Filets of sea bass float in a fennel-scented broth daffodil yellow with threads of saffron - the fragrance not able to overcome the steam-table texture. Vegetables included mushrooms sauteed with garlic-parsley butter and spiced potato wedges just like Holly Farms serves. There were something that looked like a cream puff and tasted like Play-Doh, but may have been an attempt at Yorkshire pudding. The only main dish that withstood the buffet's torture was the roast beef.

You could, of course, concentrate on the dessert table. A towering Grand Marnier souffle made a fresh appearance every once ina while, and the bowls of mousse and trifle enriched one's experience of those often debased dishes. Tiny tarts - some with raspberries - and buttercream tortes looked better than they tasted, but still weren't bad.

What it all came down to, after weeding through the meaningless and the nice-but-not-necessary dishes, was a very good dinner of liver pate, gravlax, roast beef, mushrooms, bibb lettuce salad and souffle - with or without trifle and mousse.

Is what worth $19.50 (or more like $30, if you order the lowliest among the regal wine list, and leave a small tip)?

Before you decide, let me say that you could - if you have the kind of luck we had - wait twenty-five minutes efore anyone asks you if you'd like a drink or the wine list. And, though the tables are grandly set, the buffet looks ike a misguided attempt at reverse chic. No carved ice swans, no paveed roasts or other flights of a culinary artist's fancy. The tables wear formal white skirts, but the pins show. A hole at center front remained day after day.

You can perhaps overlook this visual lassitude. But with so little service to notice, its deficiencies are hard to ignore.There is plenty of staff; only the waiters, not captains and busboys were discarded in th buffet process. At bruch, therefore, it was disconcerting to watch them all watching us. They chatted among themselves, staring with arms folded. Dinner was more bustling, but still is seemed the rule to leave the dirty dishes on the sideboard for a half hour or so - to mellow? Between these piles of ripening plates and the continuous heat being applied to the food, the dining room - at least at brunch - began to smell like a cafeteria. The refilling of water glasses could not be faulted. At brunch, though, it would have been thoughful if they had asked if we wanted coffee.

About brunch, Sunday brunch. It shows flashes of its former magnificence (after all, the chocolate-filled pastries and croissants are as fresh as flaky as ever). The delicate liver pate from dinner is on the cold buffet, along with smoked salmon and deviled eggs with a touch of second-string caviar. The hearing is fine, and the salads make a pretty still-life. But there is a peculiar recurrence of pecans, as if stirring a few into a dish made it seem more elegant. The hot buffet depended heavily on mushrooms - all right, though unimaginative. Omelets were made to order with ham, smoked salmon, cheese, mushrooms (of course) and the like. There were the makings for eggs florentine. The crepes were stuffed with tender seafood and richly sauced with wine and cream. Of course, there were sausages and bacon, along with corned beef hash and quiche that probably tasted better earlier. The highlight wasrare filet of beef with (naturally) mushroom sauce. The low point, fish filets turned leathery. Like dinner, careful choices made an excellent meal. But the fruit table lacked ambition; for a $12.50 brunch, strawberries, cantaloupe, prunes and canned figs were measly choices, considering that several other downtown restaurants had fresh figs and raspberries on their menus that week.

While $12.50 sounds high enough for a brunch, the figure is deceptively low. A bloodly mary adds $3, champagne and orange cocktail $6. With tax and a small tip, $40 or $50 a couple is not unusual. For dinner you will spend at least $60 a couple unless you're a teetotaler. It does not consiistently look or taste like such a hige-priced spread.