This is obviously too late for the OP, but for the next one who is going... I have now been living some months in Zurich and can provide the following observations:
* There is a place at the central train station (Brasserie Federal) where they have a pretty huge collection of Swiss beers. This was referenced by the OP. All lager and weissbier, except for one pale ale at the moment. I believe this is simply because that's what the Swiss beer scene looks like. The staff is unfriendly and the service is horrible, but if you're lucky enough to catch the boss (he wears a tie and staff refers to him as "chef"), you can actually have a nice conversation and get some useful recommendations based on what you like.
* For shopping, there's a place downstairs with a pretty large assortment. It's probably your best bet for picking up beer when travelling. There are several smaller, friendlier shops around town.
* The pub scene is very homogenous. Basically everyone carry Feldschlösschen, which is conceived as a local option, though it is of course Carlsberg-owned. It's an ok lager. Some other brands are available at pubs, like Calanda (don't bother), Schutzengarten (ok) and probably something else. Still nothing spectacular there.
* There are some unfiltered versions of the lagers. They are called Urtrüb or Naturtrüb and they are quite ok. You'll not run into them everywhere though. Close to the train station is an Irish pub called Kennedy's which carry the Feldschlösschen Urtrüb.
* About Irish/English pubs, there are many. They probably all buy from the same importer, because they all have basically the same options. Guinness, Murphy's, Stella, Carlsberg...
* There is a Scottish pub called Bonnie Prince (public transport stop Central, though you can walk there from the train station), where they have a variety of Scottish beers on bottles. A nice break from most of the other options in town.
* There is a brewpub called Steinfels on extended walking distance from the train station. Go to the Schiffbau or Escher-Wyss-Platz stop with public transport. It's a hipster place with ok beer. Go there if you want to support the local stuff, but don't expect to fall in love.
* A Swiss beer that you must try is Schwarzer Kristall, a schwarzbier. The bottle can be found in the decent shops (e.g., below the train station) and probably at a few pubs. I've found it at a relaxed place called Kafi für dich at Stauffacherstrase which has ok food. I wouldn't go across town to eat there, but to have Schwarzer Kristall, sure.
* A weissbier will always be a safe bet. You'll find Swiss and German ones, and whatever you have, you will like it.
Anyone who happens to find something more, please post!