Actually I use HTML-Kit, which is available from download.com for free (you may have noticed I have a real affinity for free stuff!). It's awesomely customizable, you can basically create whatever windows and toolbars you want. Also, while your work is all done code-only it has a nice Preview display that lets you see what your page will look like BEFORE you post it live.
If you want to try it I recommend you also use this guide to help you customize it to your own preferences:
http://www.ironspider.ca/hktutorials/index.htm