Well, I got a few books from my schools Learning centre, and I'll HONESTLY tell you which book was which:
Leading Edge (Dixon) - Shocking. They skim over a few key points (such as Infrastructure, which unless you actually went and read completely you wouldn't have found. Was in my test). The Chapter summaries are pretty much what you want this book for, and the definitions at the back (Just photocopy all of them for your personal use. Shouldn't be more than 25-30 pages, 10% copyright safe I think)
However, has ALOT of dry jokes, so it's easy to read though for a laugh
Riley - The Deluxe version of leading edge. If your school has a top economics and lower economics (our school doesn't have the numbers for it), this would be for the top half. Very detailed, doesn't really skimp over things, but a lack of dry jokes (you need them!)
Bulmer - The one to read. The Prelim book for it is SO GOOD, that even for your HSC w=you should use it. The Part A - C thing is also very nicely done. Also includes Dry Jokes. This book is the one to get if you're aiming really high. Just note that this book is the HARDEST to concentrate with, due to its nature. So, if you're english isn't the best, don't bother. (No offense, but read it and you'll know what I mean).
And FOR THE RECORD, only pick from ONE of the Above.
Doing economics since it was left ---> Dixon (Leading Edge)
Doing economics since I was forced by parents --> Riley
Doing economics since I need (actually) like/love the subject --> Bulmer
Now I need to go and eat my ice cream before it melts!
EDIT: Home Ice Cream eaten (Oh, and I was being serious above, if you were forced to do ecnomics please don't pick the Bulmer. You won't learn much since you won't have that driving instinct (Points at my spiky haired friend who likes 3U Maths yet gets stuck with Maths In Focus... How do you keep interest in that book?)