Although the built-in editor for Wordpress works pretty well, it still feels a little bit kludgy. If I'm on my MacBook I like to use Windows Live Writer or Textmate, but Windows Live Writer requires me to fire up VMware and Textmate seems to also be a little kludgy.
I've looked at the ScribeFire Firefox extension in the past, when it was Performancing, but the latest version seems to be almost perfect. What I've always wanted is to not only post drafts to my blog, but to also edit the drafts. The latest version of ScribeFire not only allows me to save my drafts, but I can then re-edit those drafts from ScribeFire or from Wordpress itself.
For pictures you can either select a picture on your computer and it will automatically upload it or you can do a Flickr search.
I will really be pushing it to my teachers as we increase our blogging use, and maybe put it on as a global extension on my next disk image for school.