This morning, I posted this note saying that Newsgator and VSTO2005 Outlook add-ins can't coexist, and for that reason I had the NewsGator add-in disabled so I could develop VSTO add-ins. In the meantime, I enabled Newsgator again to get a feed fix. One of the posts was from NewsGator saying they'd released a SP. I was running 2.5.9.xx and this upgrades the version to 2.5.11.xx. One feature they mention in this post is .NET 2.0 compatability.
Happy to report I can now run both my VSTO2005 Outlook add-ins and NewsGator. Way to go guys!