Many times have I heard before that the surrounds are not supposed to take your attention away from the screen, rather, they are supposed to support what is going on in the film. Their presence should not necessarily be known at all times and quite often, they aren't supposed to be known at all. The purpose of the surrounds is to give you a more enveloping feeling. To draw you into the movie just that much more. If there are specific directional cues coming from the surround sound, then you might want to check over your shoulders, but for the most part, even with directionality is used, it is not there to take your attention away from the screen. I've heard it mentioned before on the THX Demo disk and Digital Video Essentials.
The better the surround sound speakers, the more they seem to disappear.
Just my .02
Regards,
Jon
