A proper surround system is definitely nice for all those action movies when there is a lot happening "all around you". It's the little things happening in the background in more quiet moments that really makes it worthwhile.
For example when there is bullets flying all around you or a helicopter passing by overhead it makes you feel like your in the middle of the battlefield. But when there is a gentle breeze blowing around you in a peaceful moment you can easily also imagine being there in a different place. When a dog barks behind you or there is a distant rumble of thunder you are somewhere else. You can feel the mood.
Noticing all those little things has become more meaningful than the initial excitement of the action first was. It truly adds a different depth to the experience.
Sometimes it can be a bit disorienting too when the setting is jusr right. Today for example I was watching a series and there was a doorbell ringing. The sound came exactly from the direction of our actual doorbell. For a moment I was wondering whether there was somebody at the door. At the next scene the doorbell rang again, but this time the camera angle was different so the sound came from another direction breaking the immersion a little.