My job is web designer and I find that some people tend to get confused when links disappear. For instance when you click on Statistics, when you reach the stats page, the link for Statistics disappears.
I know it makes perfect logical sense to do it this way, but a lot of people have an easier time navigating if all links are present at all times, so that the menu always looks the same.
Perhaps an alternative to making the link for the current page go away, would be to simply make the link plain text instead of a link. That way the menu would all look the same, but you would not have the option of clicking on the page that you're currently on.
Just a thought
Oh yeah, suggestion #2 -- put something in the sign up that lets users choose the default for e-mail notifications so that you dont have to remember each time to click it. And of course admin would have the option to disable it completely for larger forums to prevent any kind of e-mail problem.