Does a receiver improve audio/video quality? ?

I've always used a receiver for sound management, and if you have one that will manage your video, even better. A receiver will do a better job of amplifying / recreating audio signals than a TV ever will. The TV's job is to make the picture look good, sound is an ancillary function. Having a receiver do the work of carrying the sound is a much better option than using some TV engineer's "look we can do 5 point sound from the TV" method. Just my $0.02.

Yes a receiver will improve sound quality immensely: both in tone and dimension. Your choice: small speakers clustered inside a TV chassis, OR, at least 5 multi-horn speakers and a subwoofer correctly placed around the room for surround sound performance? As far as Video quality, the technical specs of the TV and AV receiver should help you decide whether to route video through the receiver, or directly to the TV. A suggested setup: all A/V from HD cable or Sat, DVD or Blu-ray, iPod dock connected to AV receiver ( HDMI, component, composite, optical). AV receiver connected to TV via HDMI. 5.1 suround sound speaker system. AV receiver remote or a universal remote is programmed to control all.

Is your surround sound also your dvd player and tuner?