With the many sites that I have setup I have found that the Quick launch side bar was a benefit and hindrance at times. When I created webpart pages I found that by default the Quick launch bar on the left was missing. I worked around it and created other ways to navigate. This works fine on one offs or small sites, but when you begin to create larger sites it is important to have as much automated as possible.
So I was finding that the Quick launch bar on the left was needed to provide a more consistent experience. I found that a good article on the intranet on how to add this on for WSS or MOSS servers. Here is the article:
Also I found this good word document from Microsoft that goes over in detail the site navigation features and is a good guide to Web Publishing and Planning.
The article where the document link originated from: