And the winner is! Deepest Sender Firefox extention.

The Firefox extension Deepest Sender wins out over Sidebar. I like the pretty interface and its settings options better. Firefox spell checking feature works without having to type the post in a separate box like in the Sidebar. Deepest Sender also has the option to load in the sidebar but I like to use it a word processor just for WordPress.

Alas, it doesn’t let me add tags, just categories. I still have to login to WordPress and edit the post to add the tags. Until I run across something better, Deepest Sender wins.