A great improvement of Visual Studio 2005 compared to the 2003 edition is the intellisense for configuration-files. Especially complex configurations like windows communication foundation (WCF) can greatly benefit.
Unfortunatly Microsoft did not include any schema-information with the .Net 3.0 Release, so intellisense is not available out of the box. This will probably only be available with Visual Studio 2008 (Orcas) which is being release right now. But for those of you, who want to add the intellisense also to VS 2005, you might want to install the latest CTP for Visual Studio 2005 extensions for .NET Framework 3.0 (WCF & WPF). This also adds some missing developer features such as ”svcutil.exe” to generate client-proxies for the WCF.