What to do in Milan

I have a surprise trip to Milan planned for the other half's big birthday coming up in July. Main reason is that he is an opera lover so what better than to treat him to a performance at La Scala. To make the trip worthwhile we will be there 4 days - flights and hotel all sorted but hoping any v-flyers might be able to suggest key sights and things to do? Also any restaurant/bar recommendations would be appreciated!
Thanks all!

[honey lamb]

Visit the Duomo and take the lift up to the roof for spectacular views of the city.

Lots of trips to the cash machine...its very expensive!!

Thanks HL y)

Lots of trips to the cash machine...its very expensive!!

That's ok I'm a year younger than him so he will have to treat me equally for my Birthday hehe