Hey, yeah I'm in first year at ANU looking to do a development studies major and if you want to get into the development field then this major is definitely right for you. There are a range of subjects you can choose from - anthropology, sociology, political subjects, environmental, economic. Basically if you love the social sciences then you'd love this major. After the degree its up to you what you want to do but I think doing development studies really sets up the ground theory for what you want to achieve later on. It depends on what subjects you do to know what your lecturers are like but the convenor of this major is awesome - really knows his stuff.
If you plan to do this major, a word of advise is do the subjects in first year that are prerequisites for later year subjects, it will just make it easier later on..
Hope this helps.