Cole on Kingdom of Heaven
OK, so he admits that's quibbling. He does, however make the point that Saladin was definitely concerned with creating an Ayyubid state and not just defeating the Crusaders. However, his ideological program could perhaps best be seen as the promotion of an ideal Sunni state, one without the disputes caused by petty independent principalities and with a government which promoted Sunni institutions of learning and worship as well as fighting against the Crusaders who had occupied Muslim territory. For a good modern biography of Saladin, I recommend Saladin: The Politics of Holy War by Malcolm Cameron Lyons and D.E.P. Jackson, which I just added to the sidebar.
A final perspective, and one that would dovetail nicely with Cole's lamenting the lack of character change. About six years before he died, Saladin went through a near-fatal period of illness. He began to focus his attention on the Crusaders after that, and I think it was R. Stephen Humphreys who first suggested that it was the illness which on a personal level refocused the sultan from personal and dynastic ambition onto his religious duties. Motivations of people in the Middle Ages are, of course, relatively inaccessible to modern scholars, but it's definitely a thought.
UPDATE: The film definitely made Angry Arab angry.