I develop in Windows Forms and I must say that Visual Studio 2008 makes me a lot more productive. Even though I'm still developing in .NET 2.0, I can use most of the language features from C# 3 (var, automatic properties, extension methods, ...). And I really like the fact that my C# code is compiled in the background, while I'm typing, providing me with almost instant error messages (squigly underlines, yeah!).