The film is titled "War of the World's" but how boring and predictable would it be if the worlds at war were Earth vs. Alien. Spielberg takes this movie on a profoundly personal journey. The battle is really between a father and his children. Emotionally they're world's apart and the battle of wills between father and son is palpable. The disconnect between father and daughter is evident when Tom Cruise's character, Ray Ferrier, tries to calm his daughter's fears amidst chaos. He has to learn from his son how to help his daughter.
The 2nd level of interest in the film involves its Jungian influences. Tom Cruise is not battling aliens with laser canons and mindless nonsense, he is battling his own ego, externalized in this movie by the alien invasion. Only after going to the depths of his humanity can Tom Cruise's character redeem himself and rescue his familial relationships to restore the bonds he selfishly broke over the course of many years.
The film is a much more mature film than say "Batman" in that at the end of the day the hero doesn't rescue the citizens of Gotham, he merely and heroically restores balance to his family.
What more can you ask for from a summer blockbuster? Seriously?