I've been using the Blogger editor for the past couple of years (except for a while when I used Qumana) and while it's improved a lot from when I started using it, I thought I'd check out Windows Live Writer after Rick Strahl mentioned he likes it.
I like the preview features, both Web Layout, which shows just the article you're entering in the theme of your blog and is fully editable, and Web Preview, which shows what the post will look like in your blog but isn't editable.
Live Writer has lots of cool features. For example, it's really easy to insert a map or aerial view. Here's the world-wide HQ of Stonefield Software (the building is somewhat shaded by the tall apartment building just to the south):
You can also easily insert pictures, links, tags, tables, and videos. Plug-ins make it even easier to use; available at http://wlwplugins.com/ are plug-ins such as SnagIt Screen Capture Plugin for Windows Live Writer and WebSnapr URL Preview Image.
It has the usual formatting capabilities, spell checking, and lots of other features. So far, so good.