If you want the best their is, get 1Password. One of it's most useful features is autofilling the login information on webpages through a shortcut.
I use it and can't imagine using the web without it, arrive at a login page, press command+\, enter master password and your logged in.
They also have a 30 day trial for getting a feel of the application if you decide to try it.
If you don't need all that 1Password has to offer, the Mac OS included Keychain Access can also store your passwords/notes.
I had all my passwords store in there before I got 1Password.