KompoZer is a WYSIWYG html and CSS editor that is an unofficial extension of the Nvu project which, unfortunately, has not been updated since 2005 and fixes many bugs found in the latest release of Nvu. What drew me to Kompozer is that it came highly recommended on the net, has a portable version, and runs great on linux.
Lastly, Wordpress is what I'm using as my blogging softward and my posting tool. I've looked at the offerings on linux for blog posters, but so far, I have not been impressed. The posting tools provided throught the wordpress interface provide everything I look for - free, portable and runs great on linux!