Well...I wanted to vote for both, however, I use Dreamweaver mostly. But there are times I use Golive. I think the one feature that Golive beats Dreamweaver 'no contest' is site management...in fact, if I remember from a couple years ago and before, Golive has always won for their overall site management.
I've heard webmasters also mention they prefer Golive when it comes to working with quicktime movies, as well, if you intend to work or edit images on the fly with Photoshop or Illustrator, that the CS version integrates well.
I would think Golive is best suited if site management organization (site heirarchy, huge numbers of image and page files...etc) is a necessity.
Dreamweaver on the other-hand, is a lot easier to use and does integrate well with those who also work in Flash and perhaps Fireworks. Awesome Layout for it's workspace.
For anyone wanting to decide on which one to use...it comes down to what kind of websites you plan on building mostly; is extensive site management and organization important; do you work more with quicktime, or flash; are you an Adobe supporter, or a Macromedia supporter...Take that and plan it out, but also consider using both for a 30-day trial and see which one you like best for your comfort zone and workspace.
Just my thoughts anyways because both have pro's and con's