RSS Bandit nicely synchronize with Google Reader. If your read an item from Google Reader in RSS Bandit, it will be marked as read and will not show-up again when you log into online Google Reader.
RSS Bandit supports Newsgator already and with added support for Google Reader it will attract many users. Personally RSS Bandit will be my first desktop-based feed reader from now on.
Its free but only for Windows and it requires latest .NET Framework 3.5. Although RSS Bandit is small, please note that .NET 3.5 setup is approximately 200MB in size, so go for direct download if you have slow connection.
(via Digital Inspiration)