Prego's (2520 Amherst, 529-2420) always manages to intimidate me. The place is so earnest, it puts me in mind of Lenin's Tomb. A friend claims that she's never seen anyone laugh here and, come to think of it, neither have I. But I do drop in from time to time, drawn back by the superlative Mediterranean shellfish soup ($16.95). Talk about abundance. This soup has it all: lobster, shrimp, mussels, clams, oysters, calamari, scallops.... But the best part is the broth, a tomato/saffron concoction so exquisitely fragrant, I have twice in the past week dreamed about it.