Although nothing can compare to THE INVASION OF THE BODY SNATCHERS, the late 70's adaptation of the Jack Finney novel, this comes in as the second (out of four) best film version. Yes, I was surprised, considering all the negative hoopla about this movie before it even came out.
Nicole Kidman portrays a psychologist/single mother, who is conflicted about her relationship with her best friend/love interest Daniel Craig. She's also very overprotective of her son.
The actual invasion starts with the fiery crash of a space shuttle, which brings with it the organism which takes over people during their sleep cycle.
Instead of pods, the infection is this gelatenous mass that covers the body.
Kidman becomes infected and it's her struggle to stay awake or else she'll become one of them. She has to rescue her son, who is being held by the alien ex-husband, and somehow get them to safety. But there is hope, as there may be a cure for this invasion. Ironically, the cure is what keeps people in conflict and at war with one another.
Each version of BODY SNATCHERS reflects the time period in which it was made and THE INVASION definitely gives its take on the 21st century.