With respect to your question: I'd say both listening and reading are essential to improving your communication ability (especially if you espouse the "free lunch" method I follow). Reading will improve your grammar and vocabulary and eradicate errors, listening will improve your comprehension (it does little good to be able to speak well if you can't understand the response) and pronunciation (if you're lucky it may even improve your pronunciation automatically).
As for the other posts in this topic, about speaking to natives. It may be useful for you to speak to natives. But it may not. I myself found that I learned to speak reasonably fluently without speaking at all. I've only had four or five "real" native conversations in my life, but can speak better than most the people who advocate the "speak all the time" method. Moreover, my speech tends to be more accurate and less riddled with errors. I have few reinforced errors like those beginners tend to make, because until I was advanced, I seldom spoke. Hence, by the time I did speak I knew what was correct and what wasn't. My speaking skills improved without practice -- once I didn't speak in the language for over a year (not a single word spoken aloud) and instead read and listened with great intensity. When I once again spoke the language a year on I was much more fluent and my accent was much better despite not burdening my larynx in the slightest.
"[...] but can speak better than most the people who advocate the 'speak all the time' method."
This sentence should have been either " [...] but can speak better than most OF the people [...]" (which is how I recorded it), or "[...] but can speak better than most people [...]."