Kieran Clancy claims 6-7 bits of entropy per password character. If the password is vaguely memorable this is ridiculous: applied cryptography quotes various sources claiming that english is ~1 bit per character, with a small range depending on the sort of text involved.
Passwords might be a bit more difficult but 2 bits/character is probably optimistic. If use pronounceable nonsense then there will be patterns like th, po, ou, rarely having 3 or more consecutive vowels, etc.
Maybe Kieran Clancy can remember truly random passwords, which might have 6 bits/character but I, and most of the rest of the world, can't.