I used to memorize a few passwords; mentally graded as "very secure" (for things like my Google Apps and my laptop's disk encryption password), "somewhat secure" (for services like DropBox or HipChat) and then "probably insecure" (for services like Facebook or Skype). Recently I decided that the approach is simply too insecure and started using 1Password to create and manage strong, unique, passwords for every service that I used.
I'm really interested to find out what HN tends to do.
Their cross-platform support is great as well. The only thing that's missing is a solid way to retrieve passwords on Android. The LastPass "keyboard" is abysmal, and switching between their app and the one you want to enter the username/password in can be painful. I'm not sure if there's an easy way to solve this problem, though, given the sandboxed nature of mobile apps.