I've fiddled with Navisworks but nothing intense yet. I don't use Revit, but I do use Civil 3D all the time so I'm hoping for more interconnectivity between the two. As it stands the models are somewhat compatible but it's never simple.
Wish I had the chance to use Naviswork.
Such cool software.
Has Revit released a civil version yet?
I know they have Revit architecture, and I'm fairly certain they have Revit Structural.