HTTPS Everywhere forces connections on websites to be made through HTTPS instead of HTTP. I have seen a number of times where a website's homepage will have HTTPS enabled but some other portion will not be encrypted through HTTPS.
Keeper Password Manager is by far one of my favorite addons. It does a perfect job of saving usernames and passwords. It allows for the easy generation of new passwords that are extremely secure. The features that it offers for free are top notch.