Went to Milan as a large group of men. Luigi at Residence House Aramis helped us in the lead up to and during our stay.
We had an Apartment that slept 6 and the Suite that slept 8. Although the fabric of the building is somewhat dated, the apartments themselves are decently appointed for a weekend or longer stay. Beds are comfortable, rooms in the suite were large and the included WiFi is fast. Luigi is very helpful and was on call to sort most of our problems.
The building is on a side street, 200m walk from the Canal or five minutes walk from the Metro. The Navigli area of Milan is not particularly picturesque in winter, I believe it is more lively in Summer. As for nightlife - Bars were going until 2am by the Canal, or just getting going at that time in the Corso Como area. Taxis are cheap (less than 15 EURO to get to / from Corso Como), the crowd is young but out for a good time.
Overall, if you are going to Milan and you wish to stay somewhere near the Canal, then I can heartily recommend Residence Aramis.