Post. Everyone's talking about post. Pre-Crisis would murder Hulk in so many ways it's not funny.
I'm seriously doubtful whether Post-C Superman - acting WITHIN his character - would beat Hulk.
He COULD do it. If he flew out into space and then flew straight down into Hulk at super-mega-ultra-giga-hyper speeds he'd absolutely atomize the Hulk.
Problem is, he'd probably atomize himself. And the country of impact.
Also, he could win through sheer use of super-speed in a fight. He has the ability to move at almost any speed he wishes - even the Flash has said 'his muscle power snaps the laws of physics in half!' - and if he used this power to land hundreds of superman punches on Hulk every minute, then Hulk would be pulverised.
But again - though these things are possible, even plausible - he's not done them before and it would be out of character for him to in this fight.