Etwilley, you are in about the "same place" I was a few years ago.
I fealt that the system components were adequate, but believed there were some areas that needed to be addressed.
I started looking into cables and started by upgrading the power side. After that I focussed on speaker and interconnects.Lastly I addressed room treatments.
I found focussing on one area at a time allowed me to understand the various nuances and stopped me from falling into component upgrades. It also allowed me to see exactly how good each component could really perform.
I still have not changed any component, but I now know that each component is performing to its maximum ability and exactly which component is my week link.
just another approach :-)
enjoy the journey