This is the area around the famous Dome of Milan...with the big square in front and the beautiful buildings around it. There are also many shops (entrance to the Vittorio Emanuele gallery) and restaurants. Be ware of high prices.
Streets in this area are: Via G. Mazzini and Via Orefici.
This is one of the liveliest areas of the city with chic antique shops, galeries, cafes, restaurants en bars. I spend a lot of my time wandering around in the small streets of this area.
Streets in this area are: Via Brera and Via Fiori Chiari.
At the Corso di Porta Ticinese you'll find many cafes, restaurants and shops that attract a trendy, youthfully public. The San Lorenzo basilica, the columns and the mediaeval city gate are the highlights of this area.
Not so long ago this was a notorious harbor area of Milan. Nowadays it's one of the nicest places to go to (shops with second hand stuff) and to go out in (a lot of cafes and restaurants). The prices here are less high than in the rest of Milan. A very mixed public lives and visits this neighborhood. Visit it at dusk and evening.
Streets in this area are: Strada Alzaia Naviglio Grande and Via Vigevano.