I think Close Encounters of the Third Kind is one of Steven Spielberg's greatest movies. If you disagree, you might like War of the Worlds, which turns the amiable aliens of the earlier movie into the malevolent monsters supposedly more appropriate in a post-9/11 era.
Spielberg makes explicit the connection between his movie and terrorism, and it's a mistake. The 1953 version, like most science fiction of that period, is read today as an allegory about communism, and that's a useful take on the film and the genre. But I don't think most people believe the filmmakers of that earlier film put stuff in their movie on purpose so we'd get the connection with the Red Scare ... it's just something we recognize with the critical distance that comes from looking at the film and others like it with hindsight. Spielberg's already taken care of the hindsight, though ... he doesn't want to wait 30 years for people to figure out his allegorical intentions.
There are some good scenes in this movie ... my favorite is the train running full-speed with every car on fire. The special effects are impressive, as if that made for a good movie. But for the most part, this film is a failure. Tom Cruise brings little, although it's such a stupid cliche of a role (absentee father reconnecting with his kids) that perhaps that's not his fault. Dakota Fanning is good enough, but too often Spielberg merely uses her when Fanning is probably capable of offering insight into her character in a more subtle fashion. (That assumes Spielberg cares about character ... in this movie, it's enough that Fanning's character is claustrophobic and can scream real loud.) The scene in the basement where the humans hide while the aliens search through the rooms is a clear homage to a similar scene in an abandoned farmhouse in the 1953 version ... the problem for Spielberg is that his homage isn't nearly as terrifying as the original, which is one of the great scary scenes in movie history.
Meanwhile, there's the whole "they've been preparing this for a million years" angle. Here's the best advice I can give: go out and rent Quatermass and the Pit. It's not only a better movie than War of the Worlds, it actually has some intelligence behind its plot mechanisms. #557 on the They Shoot Pictures, Don't They list of the top 1000 films of all time. 6/10.