It depends on your skills and knowledge. My favorite is Visual Studio, even if you are not developing ASP.NET. By the way, you can use free-of-charge Visual Studio Express for this purpose. Please see:
http://en.wikipedia.org/wiki/Visual_Studio[
^],
http://www.microsoft.com/visualstudio/en-us[
^],
http://en.wikipedia.org/wiki/Visual_Studio_Express[
^],
http://www.microsoft.com/visualstudio/en-us/products/2010-editions/express[
^].
I have done a lot of development using plain old text editor, pretty much like Walt Fair, Jr., but it was the text editor I wrote. It has a plug-in architecture with allowed me to write text-generating plug-ins, import/export plug-ins, keyboard macro and other goodies. Basically, this is a plain editor, no syntax highlighting, intellisense or something.
For certain purposes, Microsoft Expression Web is not bad, but I mostly use it for writing simple text documents in HTML format (documenting, articles and the like), not for serious development. (I do very little of Web development though, almost nothing compared to my other works.)
I would warn against highly "automated" tools for "easy" Web development, especially something developed "graphically", with a "click of a mouse" or "drag-n-drop" (the last "feature" is the worst). Usually, it means quick development of primitive prototype but a lot of manual work for something serious, lack of flexibility, low quality, low signal-to-noise auto-generated code impossible for serious support. Those are tools for the weak-minded. Real development is usually based on coding in text and requires good understanding of each line of code.
—SA