Best residential areas of Zurich?

There are really no bad (as in unsafe) areas of Zurich, so that's the good thing. Some areas in Zurich will be better than others, depending on your priorities, of course. That said, here's my advice:

Kreis 6 (postal code 8006): This is the space between the University and the ETH, thus it's very popular with the academic types and the medical people. Prices will go between 4000 and 6000 CHF for a four-room (three-bedroom) space. T
Seefeld (8008): Located along the right-hand side of lake Zurich, south of the city. Really beautiful area with lots of restaurants, bars and the Opera House. Getting to and from the city's financial centre is easy with the tram. Again, rent for a four room (three bedroom apartment) is between 4000 and 6000 CHF.

Wipkingen (8037): a more affordable option for families - a four room place can be around 2000 CHF. Though it's relatively close to downtown, you'll need a car to get there or you'll need to take the bus.
Oerlikon (8050): reall family-friendly area with lots of parks, daycares and children's entertainment options. Four-room unit rents for 2000 to 4000 CHF.

Hi Global Nomad, not sure if you've relocated to Zurich, but we've just put together a new section on Areas and Suburbs in Zurich, so for a breakdown of the different expat-friendly areas in the city, check it out!