It can be a bit overwhelming at first.
But, it should be getting better - The reason for the massive amount of different builds floating around is that the 3.6.7 release had some problematic bugs in it, which meant people were forced to use CVS builds (builds based on the current state of the code), which in turn meant a lot of potential for confusion as the actual purpose of the CVS builds is not to be used in place of official releases, but to be used for testing new features and bug fixes. So that meant a lot of different builds floating around, all supporting different feature sets.
Fortunately though, once 3.6.9 final is done and released, that should be (and more importantly
remain) the version to have for everyone, and CVS builds will return to being used for their intended purpose. Some changes have been made to make sure 3.6.9 can recieve bugfixes
without also introducing new ones from new features, whereas before it was all or nothing. So it will be getting much less confusing once that is released

Oh, and definitely go with OpenGL, it is in far better shape than D3D support.