Someone asked that I report back on what restaurant I chose. In the end, we went with The Helmand because we'd never had Afghan food before and because several Chowhounds said it was a reliable choice. It was just right. The restaurant was hopping, even on a weeknight, but we'd made a reservation, so we we didn't have to wait. The food was good. I particularly liked the leek appetizers, the koufta challow and the lamb lawand. The atmosphere was lively without being overly noisy, and the service was attentive. After dinner, we found a "saloon" about a block away where we were able to have a couple of drinks; it felt like a real neighborhood place, a fact that was confirmed by the woman bartender (owner?). Thanks to all Chowhounds for their comments!