NDepend

We use NDepend as TL or Architect code quality control tool. In additional to FxCop and Style Cop tools. I am using NDepend to gather code project statistic. The main powerful features are
1. CQL language
2. Dependency matrix
3. Code difference explorer

CQL language - allow quick code browsing and identify most critical place of code based on the code metrics. For example detect dead code, complex methods, biggest types, methods and assemblies ...

Dependency matrix - helps me to identify cycle dependency cycles and get rid of them

Code difference - show changes between two snapshots what allow me to see interfaces changes. Very important for impact analysis.