Both have their advantages.
With a home theater, you get the luxury of watching your favourite films at your leisure.
With going to a cinema, you have the experience of watching a film with the public. Sometimes this is a negative, and sometimes it's a positive. I vividly recall going to see Star Wars Episode III, The Incredible Hulk, Spider-Man 2, The Dark Knight, Friday the 13th (2009), and more recently, Watchmen with a crowd who were VERY into the movie itself. And that definately added to the experience and overall enjoyment I must say.