At its best, Le Bagatelle is bested by none. The grassgreen trellised room is pretty and bright if you forget that you usually see Tiffany-style lamps in pubs, and the space has been artfully divided to provide a sense of privacy to many tables. Tableside flourishes add a grand note, enhanced by waiters who understand their food and wines and the necessity to make your evening a delightful one. Unfortunately, when the restaurant is not at its best, service can be slow and snappish. The wine list is impressive in its breadth, but its prices can astonish the unprepared, with little that tempts under $15, and nearly every wine priced as high or higher than anywhere in town. As for the food, a classical menu is sparked by intriguing daily specials, perhaps duck with sour cherries, an agreeable contrast to the usual sweet sauce, the duck flawlessly juicy, the skin perfectly crisp, the tableside carving graceful. The talent in the kitchen is obvious when tested on the likes of boned trout stuffed with a light puff of fish mousse, cooked precisely and sauced delicately. The standards - lobster bisque, rack of lamb, veal medallions - are prepared exceptionally well. Occassionally there are misses such as a bland, heavy fish terrine, clams tougher than necessary. Even so, there are compensations, for this is a restaurant that garnishes its dishes with artistry, the smoked trout being a handsome still life, the fish presented with a pastry crescent. Details are not neglected; side dishes might include still-crisp green beans or intensely delicious creamed spinach. Even the cheese tray offers eight ripe choices served at room temperature with fruit the waiter carves in a great show. Rare among French restaurants here, Le Begatelle serves desserts worth considerable pride, from a gateau St. Honore to a dark, rich chocolate mousse, and tarts with a buttery crunch of good pastry, though disappointingly glazed with agar-agar. Right down to excellent coffee, Le Bagatelle reaches high and, as mmuch as nearly any restaurant in town, usually succeeds.