Windsor hotel on Spring St (across from Parliament) is also a great choice if you don't mind historic older hotels (this means no 2 rooms are alike, and some are much nicer than others). It has character and is quirky but the location is superb and the bar is quite good (also European restaurant/wine bar is almost next door, some of the best food and wine in Australia). Cheaper than the Sofitel (old luxury vs. new, so the floors creak).