River sandals
Shorts or a swimming costumes
A baseball style cap, good sunglass and quality sunscreen

Shells & insulators:
Windproof & water proof outerwear, jacket & pants (goretex or nylon) Fleece jacket/sweater (wool or synthetic only for the winter season)

Clothes:
Loose fitting hiking pants (For men or women) Long underwear; tight pants can be worn under skirts if desired. One cultural note, Nepali women bath at public tap stands in a specially altered Lungi that has a drawstring above the chest. Shorts for women are not culturally appropriate outside of Kathmandu. Also, most Nepali or western men do not wear shorts either but it is acceptable.

Long sleeve t-shirt / turtlenecks (synthetic)
Short sleeve t-shirts
Several pairs of thick socks (wool or synthetic), with thin liners (synthetic)
Light weight long underwear, top & bottom (polypropylene or "capilene")
Wide brim hat (straw type beach hat or synthetic outdoors) to sunburn protection on face, ears, & neck, Underwear, etc

Other Items:
Quality sleeping bag & sleeping pad. For those who don't have they can rent it easily in Kathmandu or Pokhara.
Light weight clothing as pants, shorts, cotton underwear, t-shirts, swim wear
Light weight long sleeved shirt or t-shirt and a fleece style jacket
Toiletries (environmentally friendly is best)
Flashlight with spare batteries & bulbs
A couple handkerchiefs
Pocket knife
Stuff sacks
Biodegradable soap
Hand towel
Feminine hygiene items, including plastic bags to pack out dirty items.
Lighter / matches (for toilet paper and candles)
Spare eyeglass or contact lenses (Due to the ease of getting eye infections, care should be taken in using contacts. Disposable contacts lenses replaced frequently can lessen the risk of eye inflections.
Hard shell water bottle; one 2-liter or two 1-liter bottles ("Nalgene" or Manmade Metal) that will not melt while adding hot boiled water.
Emergency contact information; Personal medical kit.