Several spring to mind, in no order of preference you have NS14, Tasar, 470 or my pick would be an MG (Manly Graduate). An MG is a NS14 with the addition of a spinnaker and a trapeze, so as your skill level goes up you an upgrade any NS14 to a MG and have one one boat with two measurement certificates able to race in either class.
If your in QLD try a National 125. There is an active fleet up there and it's a very family oriented class. Association website is www.125assoc.com for all the info you need.
