This may be the world's only Art Deco Thai restaurant -- or at least Washington's -- but it has even more to offer than artistic charm. Thai Taste has a long menu of Thai dishes from mild to fiery, familiar to rare, and good to better to best. As with any Thai restaurant, I recommend you order heavily from the appetizer list. Mousse- light shrimp paste fried in bean curd wrapper is a delicacy, and the now-familiar satays are curry-seasoned and good. Spring rolls have plenty of crunch and flavor inside as well as out. And the old-standby stuffed chicken wings are also nicely done. Thai Taste's soups are powerfully pungent, tart and peppery. Only some of its main dishes could be characterized as mild. Pork with garlic and pepper is thin-shaved and tamely seasoned, as is chicken with cashews. Soft pan- fried noodles are homey and pleasant but no challenge to the taste buds. More punch is in the black bean sauce -- broccoli is particularly enhanced by it. Check out the daily specials, particularly the charcoal-grilled dishes such as a brightly fresh whole sea bass or chicken. In any case, the menu is vast and the prices are modest, so experimentation is in order. And the staff are eager to help explain the possibilities. 2606 Connecticut Ave. NW. 387- 8876. L, D $4.25-$12.95. L daily ex Sun, D daily. AE, CB, DC, MC, V. Res sugg. Full bar.