Windows Live Writer
While it may be sometime for the complete transformation to using XML-RPC and Atom as internal API for Spring, we get to take advantage immediately of Microsoft's fantastic (and free) Live Writer.
Simple but effective
Live Writer is a very simple application that provides a really slick editor and supports pretty much any blogging application out there.
It allows you to copy and paste images (or drag and drop), scale them, add effects, save drafts of posts locally and even load previous posts from your blog for editing.
Live Writer is fast, clean and even though it is still in beta - seems to run really, really well (at least in Vista!).