Audio is audio and video is video. Putting 2 channel through a video system is a big compromise. Now if you are talking 2 channel audio, an integrated amp will be more cost effective (and save space) since there are less boxes and cables, but separates will provide more flexibility, and probably offer the highest potential power output with separate monoblocks if your speakers or room requires it.
Moving to separates
Does anyone have an experience they'd like to share about going from just an AVR or integrated to using external amp(s)? My Integra AVR has 100 W per channel (class AB), all channels driven, and sounds very good, so it is not clear to me that there is any advantage to connecting its preouts to a separate amp. Might be a total waste of money. Please mention your specific equipment. Thanks!