Linux users have a great tool for generating secure passwords called 'pwgen'. Using pwgen, you can generate completely secure password of any length by typing a simple command.
If you don't already have pwgen installed and you happen to be using a Debian based system (like Debian or Ubuntu) you can install it by typing in the terminal
sudo apt-get install pwgen
Once the software is installed, you can generate a secure password of any length by typing something similar to
pwgen 8 1
That command will generate a single eight character password with a complete mix of numbers and both upper and lower case letters.
It's very easy to use and pretty intuitive. Now, you have no excuse to use insecure passwords again!