I've also worked on Web Application projects equivalent in size and complexity that compile in just a few seconds.
I'm open to pretty much anything, so I'd love to hear your thoughts!
This posts covers how to best optimize the build performance with Visual Studio 2005 when using web projects.
If you are experiencing slow builds or want to learn how to speed them up please read on.
------ Build started: Project: C:\...\Web\, Configuration: Debug Any CPU ------ Validating Web Site Building directory '/Web/Admin/Secure/'. VS would never even start building if that control was present in any of the open designers, though it would lock everything out as if it were building.