IC Sydney lounge is one of the best ones: very large, superb view, excellent breakfast, leisure area

Rooms with Opera view offer a superb panorama. They are rather small but elegantly appointed.

I am not a big fan of the location. The Blue hotel is definitely in a more living district.

Sofitel is a good alternative if you are looking for a nice club lounge (but no view from the rooms).

Holiday Inn Potts Point is also an excellent choice (very nice view from rooms, living and trendy district, great staff, large rooms). The Darlinghurst/Liverpool street district is where most trendy bars/restaurants/boutiques are located