The Defn of Good Sound is very subjective and depends on "what AV stiff one is used to". However from the perspective of an average listener I will suggest for seperates as below.
1. Go for a Preamplifier/processor like this.
Emotiva Audio UMC-1 Audio-Video Processor
2. Select a 2-channel stereo Amp depending upon your requirement (speaker sensitivity and ohms).
Emotiva Audio XPA-2 Two Channel Power Amplifier
3. After experimenting for a month or two, if at all Home theater is required add this.
Emotiva Audio XPA-3 Three Channel Power Amplifier
The above approach will not make any of your investment redundant at any point of time. you will have flexibility also, 2 channel, 2.1, 5.1, 6.1, 7.1. Any of the component can be updated at any point of time.
I selected Emotiva just for explaining the approach, you may go for other brands as well .
Going for an Integrated stereo amp or AV receive will always result in compromise, unless you are going for a very big budget product.
Happy listening.