Are you a developer or designer?
From the sound of it (Dreamweaver & Fireworks) you are more of a designer than developer.
Quanta that is avaiolable in KDE's webdev package is competent editor and has DW style visual editing possibility, for grpahics, Gimp is powerful and versatile. For page layouts (Illustrator replacement) check out Scribus and Inkscape).
For developer: Vim, Emacs, Kate or any other text editor you are familiar with (never seen a single developer using DW to date, but maybe I'm just working on too high-end web applications).