It's nice to think we'll get a tipping point where machines can do everything and usurp us all, but as the past few decades have shown, such robots are short coming.
Instead, it's going to be a matter of degrees - train drivers are already being replaced, next the drivers as google car (or whoever) replaces taxis, truckers and bus drivers. Pilot's after now drones are proving reliable (plus, imagine the sales pitch, who can hijack a plane with no stick?).
Machine's will start to replace most manual labour jobs given time, anything production line has mostly switched to bots already, I could foresee more people going when their role becomes cost efficient.
But Doctor's, going to be a while before they're redundant and I can't imagine many volunteering in the new work free utopia, or at least I wouldn't feel comfortable being operated on by someone who's biggest qualification is they're stupid enough to work when they could be exercising their minds with bigger issues as the world's now their oyster.
Hell, even what I do, the lofty title of Data Account Manager for a Market Research firm (basically, move numbers around and try not to lose any) can be vastly automated, as I've already started writing my own scripts, but there's still an area of critical thinking involved where judgement calls have to be made and until you've got an AI that can do that (ie, a long way off) I'm still going to be a slave to the wage.
So we're going to end up in a world with fewer and fewer jobs due to increasing automation but still be a long way from a work free utopia, at which point I believe we all go to hell as the proletariat do what they do best and think with their fists against those deemed valued enough to be employed and it all gets burned to the ground.
The upshot with that though is at least we can all go back to work.