I initially designed my site to show a login box at the top of the page if the user was not authenticated (e.g. how reddit.com works).
I encountered a user who was having trouble with their browser’s storage of their password because after a password change because their browser had stored their login information at different urls on the website. Even after the user typed correctly the new login information at one url, and the browser updated it, there would be other urls at which the browser had the incorrect login information.
This would also cause problems with sites that have a login box on their main page, and a special login page — especially if the user front page login box is sent to the login page.
Is this a small enough case not to bother with, or should there only be one url at which a user can login to prevent this problem, especially for less technically-savvy audiences?
There should be one login page that every other page accessible sans login links to. It standardizes the process of logging in and reduces the kind of confusion your user experienced. It conforms to a convention that all the browsers are using with respect to saving passwords as well. Don’t really see how you can go wrong that way.