One of the most spectacular views of Sydney, particularly the bridge and Opera House is from the North side of the bridge, either Kirribilli, Milsons Point or McMahons Point.
My personal favourite is the view from the end of Blues Point Road, McMahons Point. The arch of the Sydney Harbour bridge frames the Opera House with the city skyline as a backdrop. I can recall the first day I came to Sydney I was blown away by this view. Not to be missed.