Uhh, in your original thread, you implied that you reject cookies by default.
What do you expect? Sites can't automatically log you in without cookies. As for forgetting your password, firefox should remember passwords when you tell it to, regardless of what your cookie settings are. That only takes care of filling out login forms... you still have to submit the form.
The best compromise is to have firefox limit all cookies to the current session. Sites still work, but everytime you restart firefox the cookies (should... I haven't checked recently) all vanish.
