Organise home stuff:

Contract suspension with Swisscom (Fixnet). Cost 36 Fr.

Contract suspension with Cablecom NOT possible any more.

Inform city counsil

Divert mail to relatives (post office - 10 Fr. / month)

Check insurance (ETI Schutzbrief TCS)

Organise subletting of flat / Inform the property management, neighbours

Copy of important documents (flight ticket, passport) via email to yourself and copy to relatives

Organise stuff for on the way:

Check validity visa, passport, credit cards. VISA is a good option I think, but too expensive (4%) for cash retrievals at ATM's. EC/Maestro cash retrievals cost a fix 5 Fr. If you are travelling in a single country for a long time I can also recommend opening a bank account in that country. I did that with the Commonwealth bank in Australia.

Organise traveller cheques, cash.

Driving licence / international driving licence (or english translation). I recommend to bring the driving licence even if you are not hiring a car. you never know....

Get a travel guide. I made good experience with Lonely Planet.

Adapter www.swissworldadapter.com

Packing:

Do not exaggerate with size of backpack (you get fed up carrying a heavy bag every day). Bring the minimum  of clothes and dont fill the bag fully. There is nothing worse than having difficulties day by day to  close the bag!! Minimise number of bags - two is ideal, the big and a small backpack - even idealer if you  can stick them together.

I am fully content (so far) with my Mammut Okawango, 55l www.mammut.ch/mammut/katalog.asp?dart=3&did=11