What type of keyboard should I get for my music if I want the following effects?

The most essential thing that I need for my music is the atmospheric sound in this vid intro (It comes in at :27) http://www.youtube.com/watch?v=54GUbY32CwM I really want to know the name of what makes that

http://www.youtube.com/watch?v=DxQ_WbzjIvE (in the intro)

http://www.youtube.com/watch?v=YxLvXi5OSCg (skip to 3:35)

http://www.youtube.com/watch?v=kYXc58f0boQ and maybe the effect at the end of this video