I think there is a fine line where it tips into "unplayable" for either factor. Given how I've stopped playing several games because the story was so terrible I just couldn't compel myself to waste hours of my life playing it, I'd say I probably more often fall into the "good story makes up for bad mechanics" more often than the other way. I'm trying to remember a game that I loved the story, but the gameplay was so bad I couldn't stomach it, and I can't think of any offhand. There probably is one or two? But nothing's coming to mind.Yeah gotta disagree on that.
I'm not gonna play a game with terrible gameplay. If the story is good I might watch a lets play of it on youtube or something, but I'm not going to bother picking up a controller to play something that I'm going to hate playing just to see the story.
The best gameplay in the world absolutely can save a story that is so bad I don't care about it, because I think God Hand is awesome. Terrible story, terrible voice acting, terrible graphics and level design, and pretty homophobic, but holy shit the combat system is incredible.