What should I bring to live in Tokyo?

I will be moving to Setagaya-ku, Yokyo in the fall as I have been hired to teach at an international school there for two years. What sorts of things should I bring from Canada to help me set up an unfurnished apartment? i.e. bedding: douvet, sheets,pillows; coffee maker, pots...or are these things not terribly expensive in Japan? Also, are there second hand stores for furniture in the area?

Not terribly expensive.
Also you have to factor in the costs of actually shipping items from Canada to Japan. The costs alone you could just probably buy them in Japan.

I would just bring the cloths you need and don't bring to many winter cloths Tokyo doesn't get as cold as Canada (depends where you are)
Buy all of your things here in Japan, you can find second hand stores or even better other foreigners are leaving all the time you can buy cheap, like John said it is very expensive to bring bigger items from Canada, shipping will cost you more.

Depending on your body type you might want to bring clothes and shoes from home to last you for most of that time.

As an example I am 5'9"/175cm (I am female) with particularly long arms and legs and I am very limited in where I can buy pants and anything with long sleeves. Even though I am fairly slim I also have problems with the fit of pants and skirts- I am a bit wider in the hips, butt and thighs than many Japanese women and find that some pants and skirts that fit at the hips gape at the waist.

I take size 8.5- 9 shoes and there are few places I can buy shoes here- I do most of my shoe and pants shopping back in NZ. Bras here tend to be well padded and not available in larger sizes- if you are well-endowed consider bringing all your bras from home!

I wouldn't waste money shipping duvets, bedding and furniture from Canada when you can buy things cheaply here and then have a "sayonara sale" when you leave and sell most of it on. There are some second hand shops around but other people's sayonara sales may also be a good bet- check the classified section of Metropolis magazine (free English language magazine available in Tokyo) for an idea of what's available.

Also have a look at the Being A Broad in Japan website for advice on moving here aimed particularly at women.

Yes, you can buy most stuff in Japan. One thing I wish I HAD brought was bedding, though. If you like high-quality (high-thread-count) sheets, they are fairly expensive here. It might not be worth it to you, though, if you don't care about that.