Do society and culture, i had the same issue myself, it has turned out to be the most interesting subject in my HSC, im currently starting my Personal Interest project which is starting to take my interest and its actually really rewarding. If you apply yourself the marks and outcomes are easy to achieve and the topics are none like anything you would have previously seen in previous years. it also somewhat helps with you HSC english. Youll love it. Also HSC wise, society and culture students generally do better in the HSC because of the way the course is structured and its not as involved as Biology.
I love it, its a realyl good subject and has motivated me to not only become a seocndary english teacher but also do a double degree in Uni and teach society and culture aswell.
Hope i helped a little.