This is our 3rd trip to Switzerland. We have never stayed in Zurich overnight and we've not yet been to Basel. Questions: Is it worth spending time in Zurich? What's important to see? What's the recommendation for Basel? Thanks, in advance!
Zürich is a pleasant city to wander in for half a day, and if you add a museum (e.g. Landesmuseum, Kunsthaus) or two, it can turn into a full day.
I have never visited the museums there, but if you walk a loop from the train station to the lake and back on either side of the Limmat, wandering into the old town on either side, you will hit most highlights: Augustinersgasse, Lindenhof, the various churches, the Opera house...
We enjoyed the walking tour of Zurich in the RS Switzerland guide.