These are some books that I would use for the HSc:
Biology: Biology in Context- Oxford press, concise and good use of scientific terminology. Jaracanda is an optional although many schools use it.
Chemistry: Roland Smith (alsmost every school uses this text book) and Jaracanda- you need at least two text books for Chemistry or will miss out on avaible information.
Physics: Physics in Focus - this is a new text book written by an Asian physician who has tutored for 8 years and claimed that MOST of his students gained entry to Law/Medicine and few state ranked science courses. I really like it, concise yet specific and in depth, way better than the Jaracanda, which my school uses.
In conjuction with these books, I also used Surfing for practice, then go for the past HSC papers and last but not least, practice trial papers under exam condition.( which I have not done so far)