We got a lot of helpful information here, so thought I'd post a trip report with our experiences.
We stayed in a townhouse studio at the Hotel Krone Unterstrass, which worked fine for us though it was on the pricey side -- we like to have a kitchen. Review is here
We arrived via train from Basel. At the train station, we bought Zurich cards and a map, 6 CHF, that had a street index and a little more detail than the map you get for free. I would recommend this map if you want to go exploring. We were glad to have the Zurich cards, we prefer not to have to worry about putting together tram fare and we used the trams a lot. They were very easy to navigate, came frequently -- we just wished they were consistently air conditioned.
Some of our favorite things: we're big fans of the writer James Joyce, so we had a great time at the James Joyce foundation on Augustinergasse, just off Banhofstrasse
Joyce is buried in Fluntern cemetery, easy to get to by taking tram 6 to the end, and a very pleasant, peaceful spot -- nice views from the tram ride, too.
We really enjoyed the 1.5-hour round trip boat ride on the lake that was included in our Zurich cards. Leaves from Berkliplatz.
Most of our meals were from the Migros Take Away on the lower level of the central train station -- we found it because we arrived on a Sunday and not much was open, and it had a nice selection of salads, wraps, hot dishes, etc. Our big (big!) splurge meal was a lunch at Cafe Kronenhalle, on Rämistrasse
Elegant, and fabulous food (my husband had a delicious steak and frites, I had amazing veal in cream sauce and potato Rosti, and I'm still thinking about my starter, an avocado filled with tomato vinaigrette, so delicious!).
It was scorching hot while we were there, so we did less wandering around exploring than we usually would, and we were extremely grateful for the air conditioning at the hotel.
Again, thanks for all the helpful tips while we were planning!