I currently use Nvu (www.nvu.com) for offline blog post editing, it is a pretty straightforward WYSIWYG HTML editor that generates clean code. The only disadvantage is that it doesn't publish directly to any blogging engines, you have to copy/past the HTML.
I'm looking too. This comment was actually quite helpful, as I use Nvu--or actually, its fork, Kompozer--to build pages, but I never thought to use it for my blog.
Sucks about lack of Wordpress integration, but just copy/pasting the HTML would be much faster than linking and imaging via the http interface for Wordpress. Thanks!