Hyatt Regency, 400 New Jersey Ave. NW. 737-1234. $8.95 including champagne, coffee and juice and valet parking extra.

THE fastest growing eating mode these days, if phone calls and waiting lines are fair indicators, is Sunday brunch.So for the next two weeks this column will lead you through what was a three-month tour of the intown hotels' Sunday brunches. After a proper period of recovery, I'll look into the non-hotel brunches.

Sunday brunches and hotels are natural companions, for there is no better way to cater to the lassitude of vacation than over eggs and champagne at noon.It is, of course, all the more delicious to eat Sunday brunch at a hotel where you are spending the entire weekend. But if brunch is all you can manage as a getaway, so be it.

This week we examine the grand buffets, next week the table service versions and a roundup of lesser buffets. As you read, be warned that Sunday brunch is an invention of the devil, preparing you for nothing but an afternoon of recovering from its excess and an evening of recovering from recovering.

I have never eaten breakfast in Times Square, but I have come as close as I wish in the Park Promenade, where the soaring ceiling makes room for indoor trees, but does nothing to muffle the clatter of people and dishes. A chamber orchestra provides background for the din, and the frequent pourings of champagne make you care less about it. In Hyatt eclectic, the contemporary leathery basket-weave chairs and real cream for your coffee contrast with tawdry placemats and a green carpet repaired with strips of red tape. Lined up in giant shells are some zesty beef and chunky egg salads, a nicoise with fine vegetables, plus berries, cheeses and melons to fill in your crevices. Omelets are made to order, bland because they are cooked in "pan coating" rather than butter. Hot dishes are the standard buffet menu: winey chicken livers, carved-to-order ham, greasy hash browns, ossified eggs benedict, dehydrated blintzes and an anonymous stew. The table of cakes looks lovely -- with pink choux paste swans and chocolate-sprinkled rum balls. But you are assumed to be full by the time you reach that table, because nothing tastes as if it were made to be eaten rather than viewed. The Park Promenade is a buffet with advantages of kindly service and delicious music, good beginnings and progressive disappointments, and surcharges for orange juice ($1.50) and coffee (75 cents).