I've been us Post2Blog to post to my blog, but I don't really like the editing interface that much. Its clunky and lacks the true Windows look and feel. The interface has the hork-like feeling that you get when you use Linux UI's or the Exchange 2007 UI. Not really well done but gets the job done.
Windows LiveWriter is a very cool MS blog application that makes editing much more natural, with a true WYSIWYG interface. You can even easily add pictures, for example, here's a picture of my main workstation in my office