This is half a test post out the latest NetNewsWire Pro Beta from Brent Simmons/Ranchero. It has a weblog editor that seems pretty decent (I got it connected to Movable Type pretty easily).
I'm wondering how well it would work as just a weblog editor. I keep NNW running on my iBook since I'm trying to keep this machine as my main reading/writing machine. But there's still that need to post from other places as well. At least Movable Type allows through the web posting (Radio does too, but since it runs on the desktop, it can get hidden behind layer after layer of firewall pretty easily).