Most web browsers offer password managers and form fillers as standard, so is there any need for a 3rd party app or plugin? I think there is.
It might not be the most attractive password manager out there but I've been using LastPass now for about six months and I can honestly say, I couldn't manage without it. There are so many apps and sites that require passwords and you have people like me harping on about using strong and unique passwords all the time. The only password you have to remember is your LastPass master password. This password should most definitely be unique and strong as it's the keys to the vault. For piece of mind, LastPass uses two-form authentication.
LastPass can be added as a browser extension or as an app on your mobile device and can be synchronized between devices. It has a number of features including Secure Notes, Form Fills, Secure Password Generator and lets you test all your passwords with it's security challenge. I thought my passwords were secure until I tested them with LastPass, be warned, however this might convince you to take your password security more seriously.
LastPass free is feature rich but for $2 a month you get the premium version that includes LastPass for applications and 1GB encrypted storage. For further information, visit thedir site at www.lastpass.com.