Italian celebs whose photos hang among etchings and paintings are among generations of diners who have enjoyed this wonderfully old-world place. Ristorante Guido seems to radiate hospitality from every brick in the cavernous, vaulted dining room. Waiters in crisp jackets and ties make a special occasion of meals that might include one of the housemade pastas—pici fatti al cacio e pepe (with cheese and pepper) is a house classic—and one of several variations of grilled Tuscan beef.