Well, I must say the Hunter Valley is a great place. Although, it may not seem as big as Sydney, it has a lot of excellent studs and riding academies. There really is a great horse market in the Hunter Valley.
It caters for both english and western riders, and has some great saddleries. I live about 3 and half hours north from the Hunter Valley and I travel down their often to show, and sometimes just to go the the saddleries.
Sydney is a great place if you like big cities, but I find the Hunter Valley a lot better and it has better boarding facilities.