Does it need to be George St? There is Cafe Andaluz, which is fine for sharing tapas and sangria. They do lunch deals. Or what about Tex Mex 2, on nearby Thistle St - again they do lunch deals, and amazing frozen flavoured margaritas. Amazing pork carnitas also!
Or for something a bit different, Hendersons, for flavourful and interesting veggie dishes, both salads and wholesome dishes like hotpot and pies and quiches. It is on Hanover St. Loads more besides, depending on your prefered budget and cuisine.
Nothing wrong with Browns and All Bar One, but they are chain restaurants and there are some great alternatives.