Are you using VS2005? By default, the C# and Web profiles send only "minimal" MSBuild information to the output window. You can configure additional levels of output information by selecting the Tools->Options menu item. Then under Project and Solutions->Build and Run you can select the MSBuild project verbosity dropdown to be: "Quiet", "Minimal", "Normal", "Detailed", and "Diagnostic".
"Normal" gives me build times for projects, and is also explicit about when/where files outputs are updated and to where. This is very useful when you have pre/post actions and are trying to track down when they are firing and what impact they are having.