The Georgetown Bar and Grill is a big, sleekly handsome place, dark-beamed and oak- floored, with an aura reminiscent of a posh men's club. (But all that wood makes this one of the noisiest dining rooms around.) The service is unusually good, and the menu is watering-hole modern, which means a limited selection of everything from snacks to dinners. The food tends to be reliable, uncomplicated, solidly good. The best of the appetizer- snacks is the fried calamari, the squid sweet and tender, the batter a paragon of lightness. Soups are a good bet, too, especially the rich, cheese-capped minestrone, as are the occasional cold vegetable specials. Oysters these days are decent but nothing special. Hamburgers are big, juicy beauties, served on good, crusty rolls. Even more lovable is the Cuban sandwich, piled high with an excellent sliced pork roast, ham and cheese. The baked fish in parchment and the ginger-flavored crab cakes have been excellent lately, and on a recent visit the grilled swordfish was flawless. The duck has been admirable, too -- crisp-skinned, juicy, and with an admirably light sauce. Among the interesting and reasonably priced California wines is a lovely Kendall- Jackson chardonnay, and among the excellent desserts are a heartwarmingly old-fashioned chocolate cake, formidable chocolate and lemon mousses, and a buttery pecan pie. 1310 Wisconsin Ave. NW. 333- 7777. L $6.95-$9.95, D $10.95- $16.95. L daily ex Sun, D daily. AE, DC, MC, V. Res sugg. Full bar.