There is a good online utility called The Universal Packing List. After filling in your trip’s information, it will generate a custom packing list suitable for that particular journey.

It will return a very detailed check list. Example as follow. You definitely don’t want to bring all of items in the list along but it should be a good reference on what you should bring.

The Universal Packing List

Here is a snippet of what it will return:

Electrical stuff

General electrical or electromechanical stuff sometimes worth bringing with you.

General electrical items

Cell Phone (Mobile Phone, Cellular Phone)

Remember that there is a big risk your phone may not work in other countries.
It could be the wrong network technology, or your phone service doesn’t
allow you to use it outside your own country, or even outside your own state
in the US. An alternative is to rent a phone at your destination, but that is
probably expensive.

Charger to Cell Phone

Remember that you may need a Wall socket adapter if you wish to recharge the
batteries of the telephone, unless you have one of those new solar-powered cell
phone battery chargers.

Computer

There are many choices from Laptop, Notebook to Subnotebook. Make sure you really
need it, since many of them are heavier than you first might think! Remember that
you may need a Wall socket adapter if you wish to recharge the batteries in the
computer.

PDA

Watch

Next time I’ll buy myself a Swatch or something similar. No big deal if it gets
stolen, and they are waterproof and sturdy. Be sure the battery is fresh! Some
watches have a handy alarm feature and a built-in tiny compass. Another handy
option would be a watch with a built-in calculator, but they are unfortunately
often ugly beyond description and also seldom watertight.

Flashlight (Torch)

I have a Maglite (a thin black slick metallic torch with an adjustable magnifying
glass) that I like to bring with me. It’s nice to carry along at night in strange
neighbourhoods abroad. Kind of expensive. The smallest Maglite is called
“Solitaire” and can hang off your key ring. An alternative is the tiny,
long-lasting LED lights that cost about $10 US. Get the kind with the lockable
on/off switch for hands-free use.

Batteries

For your camera, flash, torch, watch, Walkman, PDA and GPS.

Digital Camera equipment

In many cases a digital camera is probably a better choice for a trip
than a normal camera, since they are so much simpler to handle, takes
up less space in your luggage, and are cheaper to use in the long run.
But the quality of digital photos aren’t yet really as good as normal
photos, so if you are really into this, then you’d better bring a normal
camera and normal film.

Digital camera

Be sure the batteries are fresh!

Memory cards

Some memory cards are now so large (4 GB CompactFlash are available, for
example) that you may be able to get away with a single card for the
whole of your trip. Try to estimate how many pictures you’ll take during
your trip, and how much memory they normally take up on your memory card,
and you should be able to calculate what size memory card you’ll need.

Battery charger

If your camera uses non-standard batteries, and you’re off to a longer
trip. You may also need a Wall socket adapter.

Associated cables

To your charger, or from the camera to your computer, in case you want to
move some of the pictures off your memory card, to make room for more
pictures.

Generic photo equipment

Various things to bring with you if you bring along a camera or video camera.

Camera bag

Music items

A Walkman can be heaven and hell. It can be stolen, and it can also give you some of
the best highlights of a trip.

Music player (Cassette, CD, MiniDisc, MP3)

For travels it is probably best to take a player that can read MP3 disks, since
they can store about 10 times more music, as well as many many MP3 audio books.
Particularly great if you can’t read on buses. Even better if it has a radio
tuner. There are solar cell battery chargers you can buy, so that you don’t
need to buy so many batteries. Remember that you may need a Wall socket adapter
if you wish to recharge batteries the normal way.

Headphones

Can also be a good idea on long flights, since the ones you’re offered on planes
are often of very low quality.

Music media (Music cassettes, CDs)

If you bring too many, they take up a lot of place in your backpack. If you bring
too few, you get sick and tired of them in a flash. One option is to leave them
all at home with your music player. That way all your music will be like brand
new when you come home.