If you have just come to Japan, you’ll definitely want to experience the internet that they have here. There is a great list of the various companies you can use for your internet access here.
The most cost effective seems to be Excite. From their website, they seem to use this as a way to bring in users for their adult site business.
The amazing thing about Japanese providers is they all provide email addresses with 100 or 200 MB of disk space. Wow! We are in the broadband revolution, I am surprised they haven’t made it to at least 1GB yet.
In the US, for example, Comcast has 10GB even for the add-on accounts.
If you travel much, you’ll see that Japan definitely has the best throughput for broadband internet access in the world.