lately I've been trying Opera 9.62 out while the 10 alpha is now available. I prefer that over FireFox due to seeing both a bookmarks and IE favorites folder you import from IE there. Soon a new spell checker will be available for that browser.
Whether it's IE on some occasions. FireFox, Apple's Safari, and now Opera being tried again at times user names and passwords won't be remembered automatically. Sometimes you start seeing those saved once your offline content grows as well as making a few changes in the security options. It sounds like the password manager in FF is where the problem is there.