The restaurant turned out to be Campania -- it's at 504 Main Street in Waltham. The outside is a bit unprepossessing, but the inside is relaxing and pleasant: calculated dimness shadowing a small maze of tables set in good faux-Italian decor. We took a look at the menu, and quickly sussed that it was quite a bit more expensive than I'd been planning for a random Friday-evening date, but it looked quite appealing, so we decided to go for it.
Dinner was simply excellent. Before even ordering, we got the bread basket of focaccia with an flavorful but not overly sharp puree of baked garlic. We started with the sampler appetizer, a small amount each of a number of dishes. Marinated artichoke hearts were my favorite, although the eggplant was also excellent. I liked the anchovy tart, although she gave it a miss. We followed that with the prima course of gnocchi with mushrooms, with an intensely-flavored truffle reduction covering both with the mushroom flavor. (The restaurant policy is to treat pasta as a semi-appetizer, and it was portioned accordingly.)
For the main courses, I had the pan-seared snapper, which was quite good -- crisp on the outside, with an almost meaty flavor over a good piece of fish. The duck confit that she had was better, though: fork tender and not too greasy, served with a sweet caramelized onion tartlet.
Service was just right: reasonably attentive and prompt without being oppressive. They were able to seat us without reservations at 6:30pm, but were full up by about 8pm. Dress is typical expensive-casual -- most of the guys were in polo shirts and the women in sleeveless dresses. But they didn't hassle me about my t-shirt, so they win points for lack of snootiness. (If you're able to pay, they'll take your money.)
Not a cheap dinner: it came to about $110 including two glasses of wine, tax and tip, which is special-occasion level even for us. But the meal was basically flawless, so this one is a keeper...