In general I believe less is more, and in particular when you are traveling.
If you are going on a backpacking trip to a tropical undeveloped country, here is a list of items I would recommend taking with you. In random order:
- Head light
- Small towel
- Cotton pillow case and small inflatable pillow
- Lock: often needed in hostels
- Small size bags of salt, pepper, sugar, tea bags or granulated coffee, cereal bars/ nuts: I bet you are gonna love me for this one at some point!
- Swiss knife, and spoon-fork combo.
- Rain Poncho: a thick one that covers also the pack, not one that you want to throw away after 5 min of use.
- Sealable plastic bags of different sizes. Ziplocks are just fine.
- Yoga towel: if you are a yogi, it's good for your practice on sand and decks, but also as a blanket and beach towel. I would bring also a foldable yoga mat, see below.
- Post-it & travel guide.
- Local language grammar book.
- One piece of clothing of every length and thickness, eg. one pair of shorts, one at knees, one long jeans. One warm sweater.
- Mosquito repellant and after bite remedy
- Sun block: sometimes it's expensive and difficult to find because locals don't use it in tropical countries.
- IPhone or smart phone to catch wifi, camera with great zoom and... chargers!
- USB stick and additional camera memory card.
- Hat, sun glasses, and light scarf.
- Basic drugs: pain relief, general antibiotic, and band aids.
- Washing line
- Tissues and wet tissue.
-Passport and pictures of it on your phone/camera.
- Mask & snorkel if you like to look at fishes
-Aluminum water bottle for refill: reduce waste!!!
- A foldable bag: I love the Envirosax, they're big, light, strong, and washable!
-Your favorite toiletry items: it's difficult to find your favorite brands on the road!
What about the pack?
I bought a Gregory Jade 38 and I'm pretty happy with it.
My standards were:
- min size to fit small airplane requirements but expansible and with straps outside to attach things to it;
- main space operable in several ways: from the top, bottom and front, like a suitcase;
- structure that leaves a air space between your back and the pack, to keep your back fresh
- at least a couple of additional pockets
- it must come with its own rain cover, which i use always as a protection anyway.
I found the average quality and cleanliness of the yoga mats available in the schools very poor so I would definitely recommend a thin mat to use as a top layer, or on its own. I've been using one by Manduka that is so thin you can actually fold it and perfect for traveling. I definitely recommend it!
I usually just bring cash. It's always good to have cash and ATMs abroad charge commissions as well as your bank back home. Credit cards commission are even worse, I use mine only in case there's no other alternative. I usually change to local currency once I'm there, going to an official bank. The amount to bring is up to you. $1000per month is more than enough in most undeveloped countries.
While traveling I keep the cash always in my carry on bag, along with all my valuables, never in the big backpack, and when I have a room I keep it locked there and go around with $60-70 max.
A fellow traveler, Patrick, had a belt with a zipper inside to put his cash: I think it's a great idea especially because it looks just like a regular belt.
DO NOT USE TRAVELER'S CHECKS! Very few banks accept them and they ask for a commission.