NDepend 2.0 just came out, and it *looks* to be a really awesome tool for understanding your's architecture and status, especially dependencies between components, in a visual way.
But from the demos on the site, it really does feel like you'd need to read a whole book about using it before even starting to use it for the simplest of tasks.
still, I'm pretty sure many of you will find lots of use for this, as you'll find lots of time to explore this beast of a program, which can save lots of headaches and time when it's time for that "rewrite" you were thinking of, or you want to analyze a large piece of legacy code...
My title is just me trying to be clever - it's a beast, and what you may find inside may not be pretty, but it is reality..