I've listened to some stereo, just for comparison sake, but I can't tear myself away from surround.
With stereo recordings, the really compelling, complexing thing is trying to choose sound modes. My Denon offers Dolby PLIIM and DTS Neo:6M and Matrix Stereo. I've tried them all and am having a devil of time deciding which is "best". I find myself leaning mostly toward Dolby PLIIM. I'd be interested in others' opinions.
My favorite part of the new speakers is the QS8s. I used to run a small set of bipolar Cambridge Soundworks speakers, and the difference is night and day! So much fuller and robust. The experience is substantially more immersive, to say the least.
My sub is a Klipsch I've had since about 1995. Downward firing 12" speaker with a 250 watt amp. I have no doubts that an Axiom would run rings round it, but that's just not in the cards at the moment.
Music is the best -- FZ