OP,
You have to be a little careful using watts per channel. A good audio amp with high current could provide a much better drive and sound better with much less wpc. Indirectly the current is indicated by the wpc delivered into various impedance. A great amp with high current will double the watts per channel from 16 to 8 to 4 ohms. So, perhaps 100, 200, and 400Wpc. High end audio stuff will have much higher performance for the specifications, the noice floor will be much lower… which will be satisfying at a much lower value. Surround processors put out a lot of noise and require cranking up to sound good.
To cover all the facets of getting where you want to go I recommend getting a copy of Robert Harley’s book The Complete Guide to High End Audio. You have a sense of where you want to go, and getting there on a small budget is definitely possible. But it will require very carefully chosen components. I highly recommend used ones made for high end audio.