I was always a big fan of the original couple of Alien movies by Ridley Scott. Once you got to Alien 3, it started to get a little tired and by the end of the series, it was just plain bad. I was a little apprehensive when I heard that Prometheus was going to be a prequel to the movies, but it turns out to be pretty good.
It did very well in theaters and a sequel to the prequel has already been slated with some of the original crew coming back. Many people didn't realize that this was directly connected to the Alien movies, but after watching it you'll definitely see the connections.
The androids, the creatures, etc. are all reminiscent of the original films. The crew of the Prometheus are sent to an alien planet to seek out the origins of life on Earth. They believe that they can find the original humanoid race that seeded the planet and learn more about out existence. Instead, they find a ton of dead aliens and the evolutionary ancestors of the original alien race.
It's important to note that the planet the group arrives at is NOT the same planet from the first movie. This is more of the origin planet that may explain why the Aliens look different that those from the movies. Overall, Prometheus is a great movie and reminiscent of the original films. It takes everyone back to the beginning and helps to fill in some of the gaps that were created by the movies.