I think Unbreakable was underrated at the time of its release simply because it had come straight off the back of The Sixth Sense, and it wasn't what people expected.
Now it seems to be more regarded as a very good movie by most people. It seems that people have come around to it more over the last decade or so, and hold it up pretty highly when talking about Shyamalan's work.
War of the Worlds, though not one of Spielberg's best, is still a very good movie.
That scene where Dakota Fanning walks down to the river, sees one body float by...and then hundreds of other bodies follow it was just done so well. Love that scene.
I think people rate it a bit low because it seems to take a detour when he meets with Tim Robbins. That whole sequence is done very well in my mind, but I can see how some would think it stalls the movie.
