Being a huge american football fan living in England there were quite a few american football games for the Speccy as i bought them all !
Best 8 bit computer, well for all of the 80's/early 90's i had a Speccy so i will have slightly biased views as many people do in these sort of discussions. Firstly the Amstrad was a great computer but as it came a bit too late the vast majority had a C64 or Speccy so i always put an Amstrad third.
My best friend had a C64, some games i was very jealous about (Rambo, Ghostbusters), other games i thought phew i'm glad i have a Speccy (Bombjack and others).
To me the best games are about playability, the Atari VCS has simple graphics but some great playable games, yes the Speccy had monochrome graphics but they were more detailed. The C64 were more colourful, blockier but also on the whole better tunes.
At the end of the day it depends on the programming team, Lightforce on the Speccy is a great shoot em up with no colour clash and is colourful as anything. However later in the Speccy years it seemed a case of 'right get that TV license, get a game out ASAP' and despite no colour, poor sound it would sell loads and make a profit. With the right designers/programmers great games could be produced.
But as i say its all about playability to me, the best games are the ones you obviously go back to and play, great sound adds to the experience so does colour but the best games are the playable games regardless of sound/colour.
Because it was huge in the US Commodore had a ton of great games, was very popular in the UK also and was a great machine. The Speccy was huge in the UK and other parts of Europe, not the US sadly but for me it had so many great games, so many varied games and what i miss which we had on the C64/Speccy was so many original games, dont seem to get so much of that nowadays.
With emulators i love trying different versions of games on the Speccy and C64, i love Commando on both machines which are quite different and Rambo as the C64 version is very good.
The Apple i cant say anything about really, they werent popular in the 80's in the UK, i didnt realise how big they were in the US i always thought Commodore ruled the roost back then. Someone said 250 games or something though were available ? Doesnt sound the best gaming machine.
As i said i love trying emulators, playing Atari VCS, Atari 800 or Atari ST games on my emulators on my Pocket PC/GP2X I love doing. Really takes me back to that golden age. Sorry to waffle on, just love 8 bit computers and their old games which soooo take me back to my younger years !