Not "all", but a hell of a lot. If nothing else, while using it, you'll see which features you want or not. But if we're talking purely web site functions, it has like, 90-95%. If something is missing, it means you'll want Visual studio Standard, but to give you an idea, I did a lot of consulting/contractual work using nothing but Express until I eventually made the move to higher versions, for reasons that were totally unrelated to the web aspect of my projects.
Besides, its free, so give it a try. Worse that can happen is it won't be enough :) but it really has most of it.