cambridge, and you'll ace big time. our school's got it as an actual textbook, and everyone's cruising along when they do the hsc past papers...or at least not as bad as they felt when they can't attempt any questions from cambridge...use excel as a revision thingio, i attempted some questions from it but it's not the best for laying down the basics: you'd be better off with a normal textbook, e.g. Couchman, MIF, Coroneos, Fitzpatrick, etc, etc.