I would enthusiastically add my recommendation for Senigallia. It's a beach town, so if you are there in warm weather, you can take advantage of the miles of golden sand and the inviting Adriatic.
We were there for 4 nights two years ago, in early October. Many of the beach restaurants had closed down but the weather was still warm and one was still open ... La Tartana, where we could sit in the late afternoon with a wine or beer (and abundant free snacks) with our feet in the sand. Then we returned twice to La Tartana for dinner, where we had large plates of fresh pasta and seafood for about 10 euros.
Senigallia is kind of a "foodie" mecca, with lots of other restaurants and even two Michelin two-starred restaurants, if you want a gourmet dining experience.
Aside from the beach, Senigallia is also an interesting typical Italian town, with a 17th century palazzo and 14th century castle ... and wonderful daily fruit and vegetable markets. One rainy day we walked downtown and had delicious hot chocolate with bowls of whipped cream, at La Meridiana. We had great dinner downtown too, at an osteria.
We stayed at the Hotel Palace, just across from the beach. We booked far in advance, through Booking.com, and got a great ocean-view room for under 50 euros. We wished we had been able to stay longer!
