I think I may have just responded to your Economics textbook thread.
For Legal Studies, I would highly recommend you find yourself a good HSC Legal Studies Dictionary with the Constitution in the back of the book. Most of the terminology you come across, you will be fine with, however, some words may stump you and the Internet can be a real hassle trying to find an appropriate definition. However, the real reason I mention this is for the Constitution. Being able to know various sections like s 51 (xxi) if you do Family Law, is invaluable as it gives a deeper sophistication to your argument. I do not think sitting down and memorising these sections is a good idea — on the contrary, I think that would be a waste of time — however, frequent exposure to some of the key sections will give you an edge other kids do not have.
Coming back to your question, I found that the Excel textbook is surprisingly good for Legal Studies. It provides you with a plethora of media articles, cases and statistics (be that as it may, you should endeavour to find the most up-to-date statistics). Nevertheless, it is essential that you do not just solely rely one textbook or source. I found that the Cambridge textbook often covered areas that the Excel textbook glossed over and vice versa. The Cambridge textbook also used completely different cases to the Excel book, which was über helpful as it enabled me to beef up my notes and evidence without having to do much searching at all.
If it is in your syllabus, you need to know it, so it is well worth your while to have multiple sources to ensure that the information goes in.