Hi Moira, 

Welcome to Zurich (soon) and to glocals.com. 

I'll let someone from Zurich answer your Zurich specific questions, just wanted to drop you guys a quick welcome. 

Nir

regarding the furniture.  Have you accomadation sorted?  If not then maybe leave the furniture.  Digs are really difficult to find in both zurich and geneva.  So if you come with a lot of stuff your restricting your options even further.

Bikes and ski gear, sure why not bring them.

Skiing, December is a bit early, there may be some ok snow depending how the season goes.  Id look at a couple of mess around having a laugh sessions locally before the end of the year, then delve into ski groups and more serious skiing in the new year when conditions will be better

Hey Moira, there's actually a ski group on glocals who organize ski trips out quite frequently:

http://www.glocals.com/groups/zurich/zurich-skiing-group.htm

dunno of any others but otherwise you can always start your own on here :) As for bringing your own stuff as Peaky mentioned flats aren't easy to find here but if you have an option to keep your stuff in storage if you haven't found any accomodation then go for that. Prices here are ridiculous for everything so buying everything new once you arrive could well be a surprise! have a look on sites like http://www.homegate.ch/rent/real-estate-search to get an idea of what size flats are available for your budget then you can decide on how much to bring perhaps. Good luck with the move!