What is the difference between the Google APIs Client Library for .NET (google-api-dotnet-client) and .NET library for the Google Data API (google-gdata) as they pertain to the Google Analytics API?
They are both linked to from google "Core Reporting API" pages. http://code.google.com/apis/analytics/docs/gdata/v3/gdataLibraries.html
One is linked under v3.0, and one from v2.4.
The .net library for v3.0 still appears to be in beta.
There is a comparison between v3.0 and v2.4 here: http://code.google.com/apis/analytics/docs/gdata/home.html