Hi Ben,
Best place to leave depends on what you want to be in the surroundings.
If you want public transport and nightlife, than probably Plainpalais, Paquis, old town might be the best ones...
If you have a car, and prefer to live in the 'countryside' (10 min by car 15 by bus from the center) I can really recommend the area of Bernex/Confignon. That's where I've lived for 3 years, and it is really nice. Small restaurants, nice bakery, quiet neighbourhood. The airport is 8 min by car, however by public transport it would take you around 45 min to get there...
By the way, as looks like I'm moving to Zurich (already here, but not too sure if I'm staying), my apartment might be available as of October 1
Zsofi