Maybe this is a case of premature optimization: but what if you ever need to log into a site from a public computer where you can't install your password manager.
I realized that without a password manager you're forced to choose between 1) having one super-secure password and 2) having multiple easy-to-remember passwords.
My compromise is this: have a password template. This is a string that changes in a predictable way based on the site. This could be something as silly as "password_${site_name}", making my gmail.com password "password_gmail" and my twitter password "password_twitter".
Obviously, the formula won't be terribly complex, so if I tell yo my gmail pass you can probably figure out my twitter pass given though time. But that doesn't bother me, since I'm mostly concerned about gawker-type incidents where my password is among thousands of others, in which case the bad guys will exploit the 90% of the passwords that do work instead of trying to reverse-engineer those 10% which don't.
I think that technophobes derive a great deal of their mistrust of technology from real-world blunders such as these (and fictional ones like Wargames) not realizing that "human error is normally the root cause for embarrassing failures", as the author points out.