I don't study Albert Speer as part of my HSC Modern History Study, but I do know quite a bit about him.
In regards to that statement I would most certainly agree with you. You could use aspects of his career such his role in the Germania project and the new Reich Chancellery, and probably more significantly would be his role as Armaments Minister and his role in the Nazi Regime. Under Hitler, anyone would follow his commands, it was either you 'satisfactorily abide' or you pretty much end up dead. So, also bring into your essay Speer's background and context in the Weimar Republic and the Nazi state, as when Hitler had autocratic control, in conjunction with the implementation of the Nazi Regime, every other citizen lost free will.
Something to better your essay would also to include an evaluation regarding Speer as the Nazi Architect or Speer the 'Good Nazi', when you evaluate him as a personality, you are stating whether Hitler had completely dominated Speer and thus influenced a number of his actions and decisions as a person.