Lurking on the archlinux wiki, I found a very interesting resource for choosing a strong, easy to remember passphrase. It's called the diceware method. You basically pick a die and throw it repeatedly to determine the words of your passphrase.

To associate a word with the results of the die, you are given a list of words that looks like what follows:

...
46154 ox
46155 oxyda
46156 oxyde
46161 oxyder
46162 oy
46163 oz
46164 ozone
46165 ozones
46166 p
46211 pa
46212 pacha
46213 pack
46214 packs
46215 pacte
...

The numbers indicate what word you should pick on the base of 5 throws. For example if you throw 4, 6, 1, 5, 5, you should pick the word 46155, which is "oxyda". You then repeat this process until you have 6 or 7 words. Pick the words in the order you got them, and you now have a new secure passphrase.

What I like about this method is that it is fully automated, yet perfectly secure. You don't have to worry about making a choice: the die makes it for you, and you still end up with something that is easy to remember.

Sure, I read xkcd and I was already using long sentences that made sense only if you are me, but this method beats mine, since there is no way I was picking these words randomly.

Since I could not find a list of french words, I quickly made my own.