The version number of .NET v2.0 is 2.0.50727.42 and VS2005's one is 8.0.50727.42.
The convention used for this version numbering is YMMDD, this means that the final development push was on July 27 2005, and since that time they made 42 builds.
If you want to know about the history of the .42 number check http://blogs.msdn.com/quanto/archive/2005/10/27/486052.aspx
So, after v1.0.3705 and v1.1.4322 now comes v2.0.50727.42.
Pablo