I had to learn the hard way after I moved overseas what I should have brought. Moving to a different culture is exciting and then a couple of weeks into it a bit overwhelming, so here is what I learned:
Clothes
Bring the clothes that fit you properly and feel comfortable and bring extra underwear and bras - I only brought one weeks worth of clothes and regretted it, the clothes styles that were in fashion at the time were very uncomfortable for me to wear, also find proper fitting bras and underwear has been like a search for the holy grail for me.
Leave all clothes behind that don't fit the seasons that you will be living through, for example I brought heavy sweaters that I should have left behind and didn't bring the light cardigans that would have been very useful.
Towels
If you like a really big bath towel to wrap yourself in after a shower, then bring one with you because it will be difficult to find them.
Toys and Books for the kids
If you have kids bring their toys and books that important to them, they are going to need things familiar around them to help them transition as well.
Laptop and Portable Hard drive
If you don't have enough space, put this info on a portable hard drive but on your laptop have a copy of your important documents, your favorite recipes, music you enjoy listening to, pictures of people that matter to you, and e-books or stories that bring comfort to you, and a list of all the phone numbers/emails of people you want to keep up with
Household Basics
If the place you are moving to does not have the basics, then stop off at Ikea in Japan http://www.ikea.com/jp/en/ and buy the dishes/pots/pans Startboxes (http://www.ikea.com/jp/en/catalog/categories/departments/kitchen/15939/ )The cost of shipping these items is far more expensive then buying them there and the sheets/bedding you need will be different in size than what you are used to because the bed sizes are different.
A folder to bring your most important documents in
You will need a secure folder to hold paper copies of your passports, birth certificates, life insurance docs, social security info, etc. Keep this folder on your carry on luggage. Sometimes the original documents are asked to prove your identity for utilities, bank accounts, etc.
Banking
Try and have a bank account with a bank that has branches in Japan and the US so that you do not have to go through the frustrating experience of trying to bank from a different country that does not have a branch with people that you can talk to face to face if any 'glitches' happen.
Technology
The technology you will want to bring with you are a good watch with an alarm clock, a laptop with DVD player/portable harddrive/powercords/adapters, digital camera or video camera, a good translation tool so that you can know what the words are for the important things like 'bathroom'.
The technology you will want to buy overseas is a mobile phone because the mobile phone system is different than America. You can buy cell phones that have a camera/mp3 players, etc to minimize the other stuff you bring.
And pretty much I would leave the rest of the electrical stuff behind because of the voltage issues because even with adapters you can still have problems and with Region Codes your games may not work as well.
Chocolate, spices, comfort items
If there are things that bring you comfort like a favorite type of chocolate, or a home cooked meal with a certain spice, or a favorite small item, bring it with you. Even though you are living in a different country, you will still want your home to feel like home.
Leave the big furniture behind
This was hard for me to grasp because I was so used to the idea of lots of space and I am not just referencing lots of floor space, but also large fridges, bigger beds, wider sidewalks and roads, larger cars, stores with wider isles, etc. So spatially adjusting to smaller spaces helped me realize that bringing big furniture was just not practical because not only might it not fit but trying to sell or give away the furniture in the foreign country may be even more difficult than just putting the stuff into storage.
Connect with people as soon as you can
Find a church, social group, etc to connect with people because they will be the ones who will help you understand the new culture you live in and help you with the things one needs to find like a doctor, dentist, good language school, etc.
Be prepared that change is hard but also has a lot to offer
I wish someone would have just told me this: It will be really exciting when you move and live in a different culture but there will be times when you really miss 'home' especially around the holidays and when you are in frustrating situations but the whole experience will change your perspective on life and people and you will grow as a person.
