You do have a great (and secure) password management software/hardware, your brain. Of course memorizing all those passwords is a pain and using a single password is not safe.
What I usually do is hash a password based on where I want to login using static information.
Example, you want to login on gmail: First o grab the name of the service ("gmail"), then you grab the company who did the service ("google") and then you add a salt you memorized ("kitten"). This will get you "gmailgooglekitten", then numberfy it (eg: all vowels to numbers): "gm41lg00gl3k1tt3n", reverse it: "n3tt1k3lg00gl14mg".
There you have it, a "universal pass" that is different for every login. You only need to memorize the steps and the salt (if you use it), and those are always the same.
Ps: You can use this system together with the usual password management software. :)