Hey MG. My current system is Marantz MM 7025 power amp (140 WPC @ 8), Marantz AV7702 MKI pre / pro and Oppo 105D, dedicated to audio only. Speakers are B&W 683 S2 and ASW608 sub in corner of room. All cables are Audioquest mid level stuff, for whatever that is worth. I have seen many discussions on forums about the worth of upgrading cables. Decided to put some effort into it but didn't go full idiot about it.
Don't get me wrong, it does not sound like crap or anything. I am able to afford an upgrade and REALLY miss the expansive warm sound of the old setup. We listen to hard rock, classic rock, with some classical thrown in there. Wife likes a little country every now and then... yes dear. Have been recently getting into some SACD stuff since I got the Oppo a couple months ago. Now sometimes listening to some mellow rock when I feel like "critical" listening (Steely Dan / Pink Floyd, Rush, Donald Fagen, etc).
My "old" system was the KG 5.5 with Adcom GFA 5500 and Adcom pre / tuner and various mainstream CD players over the years.
Room is fairly small 14' X 22" with one walkthrough to adjoining hallway in rear and walkthrough to breakfast nook (and subsequently kitchen) on the side near the front of the room. Also consideration is high WAF factor