It's 3:00 a.m. It's South Beach. You're certainly not ready to call it a night, but you're famished. Where to go? It must be Cafeteria, which is not a cafeteria at all but a casual resto/lounge with knockout cocktails and food based on American diner classics -- but seriously and creatively upgraded. Service can be snippy, but the supersize New Bedford lobster roll alone is worth enduring some attitude. Other terrific items include a cornmeal-crusted catfish po' boy (moist and meaty fillets of mild fish on a Kaiser roll with horseradish remoulade on the side and homemade potato chips), and macaroni and cheese (soft but not mushy elbow pasta in a mellow cheddar/fontina sauce, quite as satisfying as fancier versions costing two or three times as much). And breakfast -- which always tastes better at 3:00 a.m. -- is excellent here, too.