It's good to choose different text types for two main reasons and this applies for AoS as well
> More techniques to discuss in your essay ( eg. film = film techniques (camera shots, music), artwork = visual techniques (vectors, colour), poem = poetic techniques (rhyme, alliteration) etc.etc.)
>Shows the marker you have initiative in looking beyond the course
Make sure you don't choose texts on the HSC List - markers frown upon this because it shows you are lazy and just looked up the texts list (even if you may not have!)