I must be dense. After asking several questions on StackOverflow, I am still at a loss when it comes to grasping the new routing engine provided with ASP.NET MVC. I think I\'v
The important thing to understand is that the routes are matched in the order they are registered. So you would need to register the most specific route first, and the most general last, or all requests matching the general route would never reach the more specific route.
For your problem i would register routing rules for each of the special pages, like "register" and "login" before the username rule.