I like the Naviglia Grande district of Milan. It's a canal area with lots of interesting waterside bars serving aperitivi. Milan is one of the best restaurant cities in all of Italy. There's a lot of information about where to eat in this forum. It's hard to give you a specific restaurant for a hug, congested city, we don't know if you want a formal dinner, what neighborhood you'll be in, etc. There is a lot of information in this thread.
http://www.flyertalk.com/forum/italy...nner-spot.html