Toiletries and Medical Supplies:
REHYDRATION TREATMENT SACHETS!!
This is THE MOST IMPORTANT PART OF YOUR FIRST AID KIT when trekking in a place like Nepal. When you have diarrhoea, you get dehydrated and lose all the essential salts and sugars your body needs from your food as well as water. Therefore you MUST replace them using rehydration salts dissolved in the correct amount of STERILISED water (boiling is the BEST possible method of sterilisation; otherwise iodine).
DO NOT take immodium or other anti-diarrhoeal drugs unless ABSOLUTELY NECESSARY. If you have diarrhoea, some nasty bugs are inside your gut making you ill, and if you take immodium it's the equivalent of sticking a cork up your backside and keeping all those bugs in there to breed! The answer is to flush them out with as much rehydration solution as you can get down!
Toiletries and Medical Supplies:
If you travel during winter time, Malaria pills are not necessary, even if you go to the natinal parks, like Chitwan. - this was the advice i received from CIWEC clinic for foreigners, in Kathmandu.
Brin some mosquito repellant, especially if you travel south, in Terrai.
Luggage and bags:
I cannot emphasize enough how important it is to bring that sleeping bag. By the end of our trip, I jettisoned mine but it really came in handy while we were in both Nepal and Tibet. We stayed at Tea Lodges during our Annapurna trek, and the wannabe futon mattresses just don't cut it - plus, there are bedbugs etc. Make sure your bag has a cover so that it doesn't get wet or dirty inside. Also, since we only trekked for four days, we consolidated our stuff into one large backpack which is what our sherpa carried for us - and we left our two suitcases back at the hotel in Pokhara. We both carried small backpacks (like bookbags) on our persons, during the trek.
Clothing/Shoes/Weather Gear: The best investment I made was in my Timberland hiking tennis boots. We did so much walking I may never recover - but thanks to the thick soles of my boots plus the ankle high support, I made it without even a single blister and that's over three weeks' worth of walking. I worship these shoes now.
Toiletries and Medical Supplies: Saline nasal spray is a MUST HAVE, especially for when you're up high and it's dry. Another excellent and easy-to-tote article is sanitary hand lotion. I brought two small bottles of it and it came in "handy" for when there was little or no soap available to wash my hands. And finally, visit your doctor to determine which vaccines are needed (if you're traveling to the southern part of Nepal); otherwise, your standard antibiotic Cipro will usually take care of bacterial infections, and Metronidazole covers aemobic dysentery and yeast infections. Happy to report I had no problems on this trip!
Photo Equipment: It's a good idea to keep your film in sealed plastic bags (ziplock sandwich bags do nicely), especially when you're hiking, to protect against the elements. Film is easily found in Kathmandu and even in the villages in the Annapurna Sanctuary - but who knows how old they are. Better to bring your own.
Camping/Beach/Outdoor Gear: David purchased one of those "Camelbacks" (small water container that fits like a lightweight backpack), and this was his best investment for the trek. I didn't get one and just used bottled water along the way, which was kind of inconvenient - especially during a bad water episode. I had to throw out my bottle of nasty H2O and suck the water out of David's Camelback - thank God he had it!
Miscellaneous: The squatting to go to the bathroom didn't/doesn't bother me as much as the idea that I might not have any toilet paper - so I was pleasantly surprised to see that the villages (and many times, the tea trek lodges) have rolls of paper for sale. Not exactly Charmin, but it does the job.