Re: What we need
The C64 also benefited from the SID audio synth-on-a-chip. Unlike "chip music" from other 8-bit micros which typically waggled a DAC around to make PWM noise, the C64 was actually playing music on a viable musical instrument via simple digital registers. The most notable technical thing about it is that once you started playing a note, you didn't have to tie up the CPU to keep on playing it; ... like you did on the Speccy. Another reason why Spectrum games tended not to have in-game music but C64 games did.
Another aside: the SID was used in a couple of real synths; although their makers were always desperate for supply.
The "my CPU is better than your CPU" debate is really irrelevant when your CPU is doing everything and mine is just asking other parts of the architecture to do stuff. The same applies to Firewire vs USB.