If you’re brand new to Blender, then the build from blender.org is usually the best bet. If you’re familiar with blender development, there may be features in alternate versions of blender (work from the google summer of code, for instance), or more recent builds of blender that you’re interested in, which are easily obtained on graphicall.org.
If you want the most updated official builds of blender (as opposed to official releases, which are on blender.org – currently 2.58.1), then go to graphicall.org, click the button for your OS (bottom row of images on the right side), click the blender icon (top row of images on the right), then click the tree icon (middle row of images on the right side). This last button denotes “trunk” builds, which are typically the most stable (and least experimental) of the lot.