hi, just stumbled over this thread when searching for the nishi's store ...

you might want to add:

sala thai
zwinglistrasse (left hand when coming from langstrasse)
8004 zurich

small but very good thai store. they have a huge selection of homemade thai curry pastes
that are miles better than the packaged stuff you can buy. also spices, vegtetables, sweets etc.

motzer's imports
Baslerstrasse 102
8048 Zürich/ZH

pretty huge thai/asian supermarket!

a comment about lian hua supermarket at birmensdorferstrasse: absolutely go there if you need more chinese- than thai-oriented stuff, especially spices.

oh and then there's a tamil grocery store between limmatplatz and museum für gestaltung, can't remember name nor address.

happy shopping!