One of the cooler things about Visual Studio 2005 web development is the addition of intellisense to web.config files. And, of course, the one day that I really needed it (last Sunday) it wasn't working. Turns out there is a simple reason; there is a bug in the ASP.NET Configuration utility (the admin web pages) that changes the schema definition in the web.config file. So, if you see this in your web.config file:
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
All you need to do is remove the schema definition and viola! Intellisense returns!!!
<configuration>
VS2005 Service Pack 1???