September-April: Warm clothes, jacket, umbrella, etc.
May-August: Light summer clothes, a cardigan just in case.
Take comfy shoes for walking around.
The Swiss dress well, so if you're a fashion buff, take a couple of smart clothes along.
Toiletries and Medical Supplies: Pharmacie's won't issue some type of medical supplies unless you have a perscription. So bring your doctor's perscription along if you think you might run down on them.
Miscellaneous: Geneva is a city, and almost everything is available- you won't have a problem finding anything you need.
In winter: thermal underwear, scarves, gloves, hat. It is best to layer clothing as the shops and museums are well heated.
Toiletries and Medical Supplies: Bizarrely (because many medicines are made in Switzerland) medicines can be very expensive here, so make sure you bring your medications.
Photo Equipment: Equipment that will allow you take pictures of snow.
Tripod, as you are permitted to take photos in most of the museums but without flash.
Luggage and bags:
Winter clothes during the season, of course.
Always: a umbrella.
If you take a boat over the lake Leman it is windy: take good clothes.
Toiletries and Medical Supplies: Be careful not to eat too much (cheese and chocolate).
Don't mix drinks with La Fondue.
Luggage and bags:
Backpack or suitcase, it's up to you.
Clothing/Shoes/Weather Gear: When it is sunny it is really warm so be prepared but it can also rain really hard so take a mac.
Toiletries and Medical Supplies: All of your usuals plus take paracetamols, plasters etc.
Photo Equipment: Take a camera, I found some things quite expensive.
Switzerland is essentially sportswear country, but Geneva is more formal. Men would be wise to include a jacket--and tie, as well--if you want to try one of the city's great restaurants. A tie and sweater are standard date-night wear. Women wear skirts more frequently here than in the United States, especially women over 50, though anything fashionable goes. Except at the most chic hotels, you won't need formal evening dress.
If you need a washcloth to feel clean, bring your own: They are not standard equipment in Swiss hotels. Budget hotels occasionally do not provide soap. If you're planning on shopping and cooking, a tote bag will come in handy: Most groceries do not provide bags, though sturdy, reusable plastic totes can be bought at checkout. Laundromats are rare, so laundry soap is useful for hand washing.
To use your U.S.-purchased electric-powered equipment, bring a converter and an adapter. The electrical current in Switzerland is 220 volts, 50 cycles alternating current (AC); wall outlets take Continental-type plugs, with two round prongs.
Miscellaneous: This is a rather popular picture outside a hotel. I know there is some cute Freudian comment to be made...uh...ill save it for later;-)