I think the best little tool for remembering text fields and multiple entry text fields like bank websites, is the
Form Saver extension.
It's basically javascript bookmarklets that you can save as bookmarks, then when you return to a site where you've previously saved the data, one click from the toolbar and voila! Done!
Simply put, it's the best tool I've found for remembering snippets of info and form data.
You could use it for user name / password data but for security reasons you'd be better off with
Secure Login, especially on shared computers.