My proof, if proof were needed, is Zelda on the Super Nintendo versus Zelda on the N64. I loved Zelda on the SNES - except I can only play it with Oasis' Definitely Maybe on in the background (long story, but for me the two go together). But on the N64 it was a so-so rpg, with huge distances you had to cover to get anywhere. It didn't look as good either. Zelda on the SNES was cute. On the N64, it was humdrum. Basically the "better game" lacked playability and effectively killed off Zelda for me, although the screenshots on the Nintendo DS adverts have almost re-converted me.
Recently I've been playing PacMan on Facebook, which is further proof that graphics only get you so far and it's 'playability' that counts. PacMan has been around for almost three decades and yet it knocks many other games into a cocked hat. When I teamed up for a game of Halo with Irony Boy, I loved it, but Destroy All Humans 2 wasn't my bag. One had "playability", the other didn't. Wii Sports is the defining moment in Nintendo's triumph of "playability". Of course the graphics are something else too, but there's a reason Nintendo keep bagging awards for Wii Sports - it's simply great to play.
My favourite top thirteen most playable gamesArcade/Spectrum/other truly ancient consoles
Super Mario World
The Legend of Zelda - a Link to the Past
Super Star Wars
Super Mario World 2 - Six Golden Coins
Project Gotham Racing
Super Mario Sunshine
So what games do you rates most playable?