Thank you sooooooo so much to amaranthee for giving me the hint to a post on d-addicts about a program that allows you to watch most of Japanese channels live online.
Here is the full thread, with the list of the channels and their romanji equivalents and it's working perfectly for me.
EDIT: Found another player, smoother, with better image and sound quality, and way easier to browse: TVU Player
Once installed, just choose "Japanese" in the dropdown menu on the top-right. You'll get the main Japanese channels. Click the channel you want to watch and wait for the connection.
There is at least one minute difference from the live airing (compared to keyholeTV which is faster... but well, you don't get the quality that much), but really this doesn't matter much.
You can also double the size of the window by clicking "full size".
To make this post more interesting, here is a list of interesting stuff you might want to catch, don't forget that you can get the timetable of all the JE TV shows on WindJP.
Of course, all airing time are Japan time, so if you have a doubt about your time zone, just check this World Clock, and to make things more easier, if you're using Firefox (YAY!), you can use the very useful add-on Fox Clocks.
VS Arashi: Every Saturday from 12:59PM to 01:30PM on Fuji TV (website) Himitsu no Arashi-chan: Every Thursday from 10:00PM to 10:54PM on TBS (website) Arashi no Shukudai-kun: Every Monday from 11:55PM to 00:26AM on NTV (website) News Zero: Every Monday from 10:54PM to 11:55PM on NTV (website) Tensai! Shimura Dobutsu-en: Every Saturday from 07:00PM to 07:58PM on NTV (website) Music Station: Every Friday from 8:00PM to 9:00PM on TV Asahi (website) HEY!HEY!HEY! MUSIC CHAMP: Every Monday from 8:00PM to 8:54PM on Fuji TV (website) Utaban: Every Thursday from 8:00PM to 8:54PM on TBS (website) Mezamashi TV: Monday to Friday from 5:25AM to 8:00AM on Fuji TV (website) Zoom in: Monday to Friday from 5:20AM to 8:00AM on NTV (website) Waratte iitomo: Every Monday, Tuesday and Friday from 12:00PM to 01:00PM and every Sunday from 10:00AM to 11:45AM on Fuji TV (website) Hanamaru Cafe: Monday to Friday starting 8:30AM on TBS (website)