How long is a piece of string ?
I use (and teach) both and sometimes I switch and interchange between the two.
The answer depends entirely on your intended use and your ability and/or willingness to stick with a product and become proficient enough to use it properly.
You can build some quite complex web applications using the point and click tools built into Dreamweaver and I know a lot of developers who do just that.
In certain circumstances I fall back to the Visual Studio 2003 Enterprise Architect setup. Much of the time I also work in FrontPage.
Selecting the right tool for the right job springs to mind but Dreamweaver, since you already have it, seems a sensible choice to stay with for now.
Why not stay with it until you feel you have outgrown its abilities ?
By the time you reach that stage you will already be well advanced in your knowledge and your ability to pick up and deal with Visual Studio will be stronger. Visual Studio is not the simplest of applications to get your head around and what you already have is a very capable tool iin its own right.