mzkmxcv, …."Even 25W is good enough for most setups (if you’re speakers are 84dB sensitive and you sit 20ft away, that’s a different story)."
This has not been my experience, my speakers are rated at 89db, 6 ohm nominal, although I suspect they are a little less efficient than this would indicate. They only really came alive after I started using a 100 watt+ per side amp. Oh they played using 35W tube and 50 watt SS, but they sang with the greater power.