A few months ago, I wrote about EPWING dictionaries, a very popular format in Japan. I personally own three commercial dictionaries in this format: Eijiro (English to Japanese), CrownFR (excellent French to Japanese dictionary) and Le Concis JF (Japanese to French).
I wrote a conversion script in order to use them with a dictd server, which means I can now use them with Fantasdic. See for example this screenshot of the excellent CrownFR in Fantasdic:

The script is currently in the Fantasdic CVS and will be shipped with the next release.
Now with those dictionaries and converted stardict dictionaries, I now have very high quality English, French, Chinese and Japanese dictionaries for my daily needs. I am very happy.
The current TODO list for Fantasdic includes:
- Work on a new “matches side pane” which will allow to select and see results in case a query returns many results.
- Add support for Gtk::Print, which will allow to print definitions or export them as PDF.
- Switch from gtk-trayicon to Gtk::StatusIcon, which should bring portability to Windows.
- Add Japanese language specific features such as romaji input and word desinflection through Mecab.
- Close the Nihongo Benkyo project and use nihongobenkyo.org to run a public server with Japanese dictionaries. Include a web interface to query the server.