Personally, my own favorite Windows-based blog editing application is Windows Live Writer. It's totally free, easy to use and did I mention totally free? Windows Live Writer is a FREE, Windows-only offline blogging software program. Fully integrated with other services of the Live family, Live Writer supports spell checking, and the embedding of any media content. Not supported: tags, pings, multi-blog posting, and Twitter notifications.
http://windowslivewriter.spaces.live.com/
There are many other desktop applications of great quality and they can be found on the internet for Mac and Linux users.