We do our own routing with Agility CMS, however we are looking at switching to the more standardized routing built into Asp.Net (as of 3.5sp1).
I think the capabilities built into Asp.Net 4 will be what kicks us in the pants enough to update our logic, though, as it has some cool features and enough end-to-end link management utilities to make it work for our developers without asking them to re-learn the re-invention of the wheel again.
Scott Guthrie outlines some stuff here that describes how to use this mechanism in MVC 2.0 and Web Forms 4.0.
more later - joel