1.0 obsolete
1.1 VS 2003
  * win 2003 has built in

2.0 (sp1) VS 2005/8/(?)10
3.0 WPF, WCF, WF, VS 2005/8/(?)10
3.5 (sp1) Linq, C#3.5, Entity fw..., sp1: System.Web.Abstraction, Sys.Web.Routing. VS 2008/(?)10
  * win 2008 has built in
  * the same runtime
  * upgrade is convinient (not risky , backward compat)

4.0 VS 2010
  * new machine.config, mscorlib, runtime
  * C#4.0, ASP.NET 4.0
  * upgrade might be risky, requeres changes in web.config.

  * integration with VS
  * MonoDev
  * The Mono API today is somewhere in between .NET 2.0 and .NET 3.5,
  * cross platform



we recommend:

VS 2008/.NET 3.5
  * C# 3.5
  * all-in-one technologies.
  * upgrade from .NET 2.0 does not require any code change

MONO for cross platform only.

VS 2010/.NET 4.0 - in the future.



Hi. I want to add some words about IDE's. VS 2010 is good tool to develop: comfortable code editor based on WPF(zoom in), new architecture features like generation sequence diagram, view call hierarchy and etc. Possible to work in parallel with VS2010 and previous VS - just save old solution file (depends on projects type - on class library, win service and console projects works proper). SharpDevelop: easy, fast, grows quickly, supports most project types, open-source. Very suite for sources observing, less for "deep" development(currently). Notepad++: very comfort to view single source files, supports highlighting of most languages and formats. Regards, Michael