[ufmace]

I think even the 20k most common estimate is way high. Think up some words yourself, and look them up in a frequency list. Most of the stuff I came up with of the top of my head was around 4-6k down the list. Look down to 20k and you get stuff like decorum, decked, daylights, daybreak, etc. When was the last time you heard anybody use those in a conversation?

I bet that with a little work, you could come up with a list a few thousand long that would get most of the passwords people come up with like that.

For my memorable passwords, I switched to using [0] pass phrase generator, which comes up with much rarer words than I do off the top of my head.

[0] http://www.fourmilab.ch/javascrypt/pass_phrase.html

[1] http://www.wordandphrase.info/frequencylist.asp

[2] http://en.wiktionary.org/wiki/Wiktionary:Frequency_lists