Although this remake of the original "Day" (circa 1951) is not uninteresting--switching from global concerns over the Cold War to environmental issues--there just isn't much to see here. Keanu Reeves does a decent job as Klatuu, the alien come to Earth to warn its inhabitants about their pending self-destruction, and Jennifer Connelly (as an astrobiologist) is fine as well.
However, if there's any part of this "Day" I could do without its Jaden Smith (son of Will) as Ms. Connelly's irritating stepson. The kid also can't emote his way out of a paper bag.
Otherwise, "Day" isn't a bad movie, just a fairly unremarkable one.
PS: A trailer for "X-Men Origins: Wolverine" runs before "Day" in most theatres. I'm hoping the actual movie (due May 2009) will be much better than the snippets I saw, including Taylor Kitsch as Gambit.