Zurich is a lovely city to wander around whether you are wandering along the Schipfe, the Artisans street on the River Limmat, or Niederdorf in the old town. Take time to relax with a coffee in one of the riverside or street cafes.
I would recommend the climb up to ETH Zurich as you get a fantastic view from the Polyterrasse across Zurich. Well worth the climb although you can take the Polybahn up. (funicular railway) Be warned that at lunchtime the place is hoaching with students from the Universities.
Another recommendation would be the boat trip round Lake Zurich which gives you fabulous views around the city.
After the boat trip you can have a relaxing seat in the Sechse-lauten Platz overlooking the fountains outside the Zurich Opera House.
One thing I cannot recommend though is the Alpine pasta dish which is macaroni and cheese with apple sauce, an acquired taste I think.