I have to admit that I was skeptical, since I am a huuuuuuge fan of the original filmed version from 1953 (with Gene Barry and Ann Robinson) produced by the legendary George Pal. It was an extraordinary achievement for its time (it won the Best Special Effects Oscar for that year), and it was well-produced in all respects.
Well, surprise! I like the new version even better!
For one thing, it is actually more faithful to Wells' original story than the Pal film: the Martians (although they are never identified as such in the new film) get around in giant "tripods", just as Wells described them; they use a "heat ray" to vaporize humans and, just as Wells said, they are bloodsuckers!
The new special effects are, of course, up to the finest modern standards, far surpassing the award-winning originals (there is a scene with a train on fire that is mind-boggling!). We even get to see Tim Robbins standing in for Wells' "curate". I wonder why Spielberg didn't make him into a preacher of some sort (could it be that he didn't think the audience knew what a "curate" was?
). Also gone are a lot of the gratuitous religious references from 1953 (the Martians, perhaps, were meant to stand for the "Godless Commies" back then
), replaced by updated references to terrorists (at one point, little Dakota Fanning [who is an amazing little actress, BTW] screams "Is it the terrorists?"
).
Anyway, go see it--you won't regret it.

I'd say that he plays the main character in a believable fashion. I think given what he goes through (such as running down a street with people being killed all round him and being covered in their remains) it's understandable that he suffers from a good deal of shock and isn't able to just get a grip.
