How do the .NET Framework, CLR and Visual Studio version numbers relate to each other?

Question

With the recent announcement of .NET 4.0 and Visual Studio 2010, it is becoming ever more difficult to keep track of what .NET Framework versions build on what version of th

Answer 1

Note that while 3.0 bascially only added new assemblies (same CLR), 3.5 added new assemblies, new compiler, and updated the CLR to SP1 level.

Framework 4.0 will be a whole new CLR (4.0, no CLR 3.x) which will run side-by-side with CLRs 1.1 and 2.0. It will also have all-new assemblies versioned 4.0 instead of using the 2.0 assemblies.

Framework  CLR and Assemblies            Release
----------------------------------------------------------
1.0 RTM    1.0.3705.0                    Visual Studio .NET (aka VS.NET 2002)
1.0 SP1    1.0.3705.209
1.0 SP2    1.0.3705.288
1.0 SP3    1.0.3705.6018

1.1 RTM    1.1.4322.573                  VS.NET 2003
1.1 SP1    1.1.4322.2032
1.1 SP1    1.1.4322.2300                 Windows Server 2003

2.0 RTM    2.0.50727.42                  Visual Studio 2005 RTM
2.0 RTM    2.0.50727.312                 Windows Vista
2.0 SP1    2.0.50727.1433                Visual Studio 2008 RTM and .NET 3.5 RTM
2.0 SP2    2.0.50727.3053                Visual Studio 2008 SP1 and .NET 3.5 SP1
2.0 SP2    2.0.50727.4016                Windows Vista SP2 and Windows Server 2008 SP2
2.0 SP2    2.0.50727.4927                Windows 7

Framework  CLR           New assemblies
----------------------------------------------------------
3.0 RTM    2.0 RTM       3.0.4506.30     The only "out-of-band" non-SP framework release
3.0 SP1    2.0 SP1       3.0.4506.648    Visual Studio 2008 RTM and .NET 3.5 RTM
3.0 SP2    2.0 SP2       3.0.4506.2123   Visual Studio 2008 SP1 and .NET 3.5 SP1

3.5 RTM    2.0 SP1       3.5.21022.8     Visual Studio 2008 RTM and .NET 3.5 RTM
3.5 SP1    2.0 SP2       3.5.30729.01    Visual Studio 2008 SP1 and .NET 3.5 SP1
3.5 SP1    2.0 SP2       3.5.30729.4926  Windows 7

Framework  CLR and Assemblies            Release
----------------------------------------------------------
4.0 RTM    4.0.30319.1                   Visual Studio 2010

(This was collected from various answers and linked documents, especially the MSDN article How to determine which versions and service pack levels of the Microsoft .NET Framework are installed linked by DOK.) A full list with KB update versions and support retirement dates can be found on Wikipedia, List of .NET Framework versions.