For many coders just getting started, or even seasoned coders who feel Visual Studio is a bit out of their price range, there's a fantastic, free, open-source application that does most of what VS does, and has some great extras. We use it here almost exclusively, and are very pleased with it.

Of course, for anyone who came from a text-editor background and has since used an IDE such as Visual Studio or Eclipse, there's just no going back in most cases. With code completion, refactoring support, folding, syntax hilighting, and all the other bells and whistles we developers get spoiled on, even an expensive IDEis often worth the price.Not using an IDE these days is like writing a book. Literally, with pen and paper.

SharpDevelop is a free, open-source IDE for C# and VB.NET. They have since added support for Boo, F#, and Iron Python as well. It also includes a GUI for WixInstaller projects, integrated NUnit unit testing and PartCover code coverage, as well as the SandCastle documentation generation tool. It even has integrated Subversion version control integration.

It is fully compatible with Visual Studio projects (including the new version 9.0 format), so you can work on the same projects and solutions with either SharpDevelop or Visual Studio.