A more *exact*: Is .NET Languajes. VS.NET is not absolute necesary, is only the first IDE for that plataform.

For example, sharp have a free IDE, and Borland (www.borland.com/delphi) is building a competitive IDE. In this moment provide Delphi 7 with Win32, Linux y a preview of a .NET compiler... very nice (Check the PDF if you want to know)...