Harry Potter and the Half-Blood Prince took the weekend box office crown with an estimated total of $79.5 million, which brought its five-day cumulative to $159.7 million, the best opening in franchise history.  Overseas, The Half-Blood Prince set a new record earning an estimated $237 million over its first 120 hours of release.  Warner Bros. delayed the debut of the sixth Harry Potter film by more than six months in order to bolster its strike-weakened summer schedule, and the pent-up demand among fans of the series was evident in a record opening day domestic gross for the franchise of $58.2 million on Wednesday, a figure that includes a record-setting $22.2 million from midnight Tuesday shows, a total that eclipsed The Dark Knight’s $18.5 million midnight start.

Weekend Box Office (Studio Estimates): July 17-19, 2009

As potent as the new Potter film’s debut was, it still couldn’t match that of Transformers: Revenge of the Fallen, which brought in $201 million during its first five days of domestic release.  While this means that the chances of the sixth Potter movie catching the Transformers sequel in the domestic box office derby are slim, the Potter film will get additional IMAX exposure (at Revenge of the Fallen’s expense) starting July 28th, which should provide The Half-Blood Prince with some decent legs.

The powerful Potter performance also couldn’t save the box office from a steep 39% decline from this same weekend last year when The Dark Knight debuted.  For the summer season Hollywood remains 4% ahead of last year, but it is unclear whether G.I. Joe and the other August releases will be strong enough to keep summer 2009 totals ahead of 2008.

One thing is certain, the Harry Potter franchise, which so far has grossed $4.5 billion worldwide, remains strong.  The Half-Blood Prince, which has received one of the highest percentage of positive reviews in franchise history, is off to a strong start both domestically and overseas, where two-thirds ($3 billion) of the series’ money has been earned.  The performance of The Half-Blood Prince certainly bodes well for the two final films in the franchise, which will be directed by Prince’s David Yates and will open in 2010 and 2011 respectively.

As for the rest of the top ten, Fox’s Ice Age: Dawn of the Dinosaurs dropped just 36% in its third weekend bringing in an estimated $17.7 million and driving its cumulative to $152 million, while Transformers: Revenge of the Fallen earned a still potent $13.7 million and brought its 2009-leading total to $363.9 million.  As predicted here last week Sacha Baron Cohen’s Bruno dropped like a stone, falling nearly 73% in its sophomore session as it tumbled to fourth place.

Both the well-reviewed comedy The Hangover and the near universally-panned "romcom" The Proposal remained strong options at the box office.  The Hangover in particular, which has now earned some $235 million, looks like it might well overtake Star Trek ($253 million), no mean feat for a film that was made on a $35 million budget.  Pixar’s Up remained in the top ten for the eighth week and brought its cumulative to nearly $280 million.

The “anti-romantic comedy” 500 Days of Summer from Fox Searchlight and Kathryn Bigelow’s The Hurt Locker from Summit Entertainment are doing very well in limited release and are worth keeping an eye on.