The "register" link seems to be conditional and only shows to a visitor not already registered.
If this is correct, and its not just a native function of WP, why not make the others conditional? The user doesn't need to see the login link when he's already logged in, likewise he doesn't need to see logout link if he isn't.
Also, I like to change the colors of the buttons depending on their function, so this means ~ as its configured at the moment ~ I can't use the login|logout button since it would always be styled with the same color.
At the moment I am getting over the conditional problem by using this plugin ~ If Menu ~ but it would be much better if its functionality was already built into this one.