First things first, have you calibrated your receiver to confirm that all the channels are operating and outputting at the same level? If that's been done, then what you hear (or don't hear) is the result of how the source material is mixed rather than the set up of your equipment.
With most programs, most of the sound will come from the front speakers. Feature films tend to have more sound in the surrounds than other programs. Live TV shows such as the NCAA tournament are mixed to make sure they sound right in stereo. There will be some ambience in the surrounds, but little else.