Being off the beaten track seems to fit Marco's. Located on the fringes of the Old Town commercial district, its hideaway atmosphere is enhanced by the masterly piano playing of Lenny Williams.

Play it again, Len, and he does. From his piano bar near the entrance, he weaves seductively through all the old favorites such as "April in Paris," "Someone to Watch Over Me," "When I Fall in Love," "Misty," and so forth. In the soft light, lulled by the music, your mood mellows, which is helpful because the service can be as leisurely as the music.

At its best, the service is unobtrusive and efficient; at its worst, awkward and lacking finesse, typified by the glib comment by one waiter that a patron who had become ill should have gone outside. For a restaurant banking a lot on its intimate atmosphere, flipness can be fatal.

The menu is uncomplicated and continental in flavor. The specials, recited by the waiter, tend to be more expensive than the regular menu items that range from $10.95 to $14.95.

The food is generally good and attractively presented. Each entree is preceded by a generous salad -- tossed and dressed from a cart wheeled to your table.

The entree plates are decorated with a trio of vegetables that may include a pretty orange rosette of pureed carrots and potatoes, followed by two lightly browned potato puffs next to a tiny muffin-sized serving of broccoli souffle.

Entrees, like the shrimp and scallops jardiniere, are colorful as well as tasty. The pink medium-sized shrimp and white scallops are surrounded by chunks of celery, carrots and potatoes bathed in a light sherry-spiked cream sauce dotted with fresh parsley.

For good quality veal in a delicious salmon-colored Dijon mustard sauce, the veal Dijon is a bargain at $11.95.

The brown sauce on the roast half duckling adds richness to the tender and succulent meat with a minimum of fat.

Another good entree, if somewhat heavier, is the chicken Cordon Bleu. The perfectly browned chicken is wrapped around a tasty filling of melted cheese with chunks of ham.

Fortunately for Marco's, a game warden wasn't served our brook trout Bretone. Although it was nicely cooked, the wee thing was barely big enough to keep. A dash of lemon adds zip to the fish, but the mini-shrimp and mushrooms sprinkled on top seemed an afterthought.

With the exception of the trout, the portions are certainly adequate, but would not preclude an appetizer or soup.

For big appetites, the hearty onion soup au gratin is a good choice. A delicate watercress soup with a light buttery broth or the creamy New England clam chowder with big chunks of slightly chewy clams were the other possibilities.

The appetizer list is heavy on shellfish and old standbys such as oysters and clams on the half shell, mussels or escargot with garlic butter and a plate of the day.

Other appetizers include the four jumbo shrimp in the ordinary shrimp cocktail or the six clams in the clams casino. On the night we tried the latter, the clams were so tough -- virtually indestructible -- that chewing one small clam could have kept you busy all night.

On a tastier note, the beautiful desserts, like the salad, come to you on a cart. Although the selection changes frequently, a representative sampling of German chocolate cake, draft cake and a four-layer praline cake brought forth compliments from fellow diners.

The wine selections, displayed in a notebook with sample labels and capsule commentaries, are reasonably priced. The food at Marco's, although good, is not exciting. The draw at Marco's is the combination of good standard fare, an attractive, intimate setting and the engaging melodies of Gershwin and Porter on the piano. If you're not looking for trendiness but want a pleasant, relaxing evening in Alexandria, Marco's is worth a visit.