Windows Live Writer with Textpattern
I like Textpattern as a blogging tool myself but it's not so great for clients who want to use it to update their own websites. The main reason is that Textile (even though it's a simple way of manipulating text), which is the editing 'tool' in Textpattern, is not familiar to many non-techie people. What they want is a familiar (dare I say it) word processor-type interface.
At the same time, I want their websites to be standards-compliant and follow the same coding standards as Textpattern. These two (apparently) simple things are often not achievable.
The other thing that I would find useful is the ability to 'blog this' from an RSS item in FeedDemon. Now that would be great.
I'll report back in a few days…