I use Ubuntu Linux on my desktops, and I prefer to use plain old gedit (the built in text/code editor) for 99% of my work. It's got automatic syntax highlighting for tons of languages, is easily configured to suite your preferences, and of course it's free.
For me the best html editor is dreamweaver. Its easy to use and I have created many of my website with it.
Notepad++ its great and free Dreamweaver its nice and has WYSIWYG (what you see its what you get) editor which rocks, and autocomplete, etc.