Any of the billion flat text editors / notepad replacements, a copy of filezilla, and the actual browsers.
The mere notion of a WYSIWYG for web development is absurd since between different OS, font stacks, screen sizes, default font sizes, font renderers, etc what you see on your machine is actually unlikely to be what a visitor to your site gets.... or even wants.
Sure you can use DW just in editor mode, but then all you've done is blow several hundred dollars on an overglorified copy of notepad, a webkit (formerly Opera) based browser window that doesn't actually render like any existing browser, a mediocre/stripped down FTP client, and a 'project management' tool that usually either abused to do php's job, or just makes an even bigger mess of the markup shoving comments into your code that are mostly just likely to break your layout in legacy IE.
As Dan used to say, "The only thing about Dreamweaver than can be considered professional grade tools are the people who promote it's use."
I extend this to anything that has a WYSIWYG editor in it. Do not waste your time with any of that buggy, broken, bloated, overpriced (even when free) nonsense.