I recommend the Hotel Helmhaus in the old city and liked it very much. I booked the hotel through the Zurich Tourism office at http://www.zuerich.com because they were having a special at a few hotels (Helmhaus was one) where the kids got a whole room to themselves for free as long as the parents were paying for their own room. They gave us a coupon to eat at a nearby Italian restuarant where the kids ate free and the food was really good.
It sounds all too good to be true, but it WAS true. You can look at the website
I just sent an email to the Zurich Tourism people via their website. Maybe it will work for you, too.
By the way there is a cinema close by where we were able to see the 2nd Harry Potter movie during its release...in English! That was a blast.