I'm posting this from NewsGator 1.2 which has just been made available for download. I only installed NewsGator for the first time yesterday but should have done so sooner. Its an impressive piece of work by Greg Reinacker.
Interesting to note that the XML-RPC-based plugins use XML-RPC.NET. Also that a different plugin is required for each type of blogging engine. I'm using the MovablePoster plugin from Matt Berther. This works well but does not quite fit into my way of working with Movable Type. I use a text formatting filter with Movable Type and I'd prefer the plain text of the entry to be posted to the blog rather than an entry with HTML formatting inserted by the Outlook editor. This would also require the ability to set the text formatting type for the blog.
The killer posting feature for me would be the ability to save a draft in Outlook without posting. Currently doing a Save posts the entry to the blog.