It took a while, but we just released a new version of the .NET client library for the family of Atom Publishing protocol based Google Data Apis. There are a lot of changes in this release (you can find the full release notes here:
http://google-gdata.googlecode.com/svn/trunk/clients/cs/docs/generated/RELEASE_NOTES.HTML) , but the most notable changes are listed here.

Visual Studio Project Templates

It was never so easy to get going. When you use the setup program, 6 project templates are placed into your Visual Studio template folder. Now, just use "New Project" and pick the template you like. You get a minimal, but working, Google Data API application. They use a common login dialog, log you in, and display the result in a listview. Easy to start, easy to modify. If you choose the archive download, just copy the templates from the subversion repository to your Visual Studio installation.

Better Visual Studio integration

After installation, the Google .NET assemblies are now registered, so that they show up in the "Add reference" dialog. No more searching your harddisk to find the just installed SDK...

.NET 2.0 and upwards

The code is slowly moving to the present, and support for .NET 1.1 was removed with this release. Generics and other features just make the SDK perform better and easier to maintain. Something that will help us in adding more features in the future.

Support for Google Contacts

There is support for the Google Contacts API as well as a project template to get you going.

You can find the release here:

http://code.google.com/p/google-gdata/downloads/list

and if you happen to find bugs, have suggestions, please post them here:

http://code.google.com/p/google-gdata/issues/list

Regards