Kings Kurry is OK to good.
It's main attraction: completely non-smoking.

A bit further out is Korma Sutra:
http://www.kormasutra.ch/portrait.htm
at
Witikonerstrasse 375
8053 Zürich

I was there for a leaving do a few months ago and very nice food.
Almost on par with a decent British Indian place (or have I been here too long... )