How to pick a good backpack
Being a backpacker you'll need to get a backpack and if there is one single object that it is worth spending money on, this is the one. You'll be largely living out of the bag so you'll need something that is both durable and comfortable.
A word on cheaper backpacks in Asia. Once in Asia you'll be able to buy ripoff backpacks tagged as the real deal, often for as little as US$30. The main problem with these packs is inferior materials and poor stitching.
The stiching unthreads and the bags fall apart quicker than you'd expect -- especially if you've got you bag full to the brim. We've bought at least a dozen of these over the years and our store-room is full of broken, torn and generally unusable cheap packs. We've also got an authentic pack purchased in Australia for around A$300 in the early 1990's and it is still going strong. Sure it could do with a hose out, but the bag itself is solid and probably will be for another decade.
Pay the money and save yourself the grief of the cheap rip-off bags -- they're passable for a short-term day-pack, but as a main pack, buying one is a mistake.
Things to look for in a pack
Don't get one that is too big. Regardless of what size you buy, rest assured you'll fill it, so the smaller you buy, the less you'll need to carry.
Make sure it is comfortable as you'll be wearing it every other day.
Make sure the straps are sturdy and that there is a waist strap (which transfers almost half the weight of the pack onto your hips).
Make sure it has an internal frame.
Make sure it is waterproof.
Make sure the zippers have "eyes" that a padlock or security wire can be threaded through.
Does it have a day-pack? A day-pack is a small mini-backpack that attaches to the main pack and can be useful for ... you guessed it ... day trips.
Planning your trip
Less is more
Don't over-plan
How to save time
Travel gear
How to pick a good backpack
Money belts and security gear