QTM - QTM is a blogging client which is presently capable of composing, formatting and submitting blog...
Open Live Writer - Open Live Writer makes it easy to write, preview, and post to your blog.
SeMagic - Client for LiveJournal, Blogger, Wordpress
MarsEdit - MarsEdit is a desktop blog editing application for the Mac. It provides an offline interface to most popular blogging systems. WordPress, Blogger, Tumblr, Movable Type, and many other systems are supported.
Scrivener - Scrivener is a content-generation tool for composing and structuring documents.
Blogo - The easiest & fastest way to write, publish & manage blogs