Security vs. Convenience
Although my intent is not to start the next GNOME/KDE-level war, it seems there must be a happy medium between total desktop insecurity and total desktop unusability. Linux offers so many ways to secure data that it's important to realize it's okay for folks to have different needs and desires. Sure, there are some basic security measures we all should take—things like:
* Don't write your password on a sticky note fastened to your monitor.
* Don't leave your e-mail account logged in on a public computer.
* Keep your system updated.
* Do have a password.
* Don't use “password” as your password.
Apart from that, and I'm sure a few other common-sense practices, security is different for different users and different situations.