I vote for Jack. It would be interesting to see the percentages of the ages of people who vote for Tiger vs Jack. Lots of golfers nowadays haven't seen Jack Nicklaus in his prime. No surprise that Tiger is outpolling Jack. And when Tiger's career is over, if he has more majors than Jack I don't know how anyone could argue against him.
But whenever you compare athletes of two eras, the older ones (especially pre-TV footage & pre-ESPN) tend to be downplayed. LeBron is awesome, but how many 18-30 year olds will even mention Oscar Robertson? (BTW, Kudos to LeBron for knowing who the Big O is while LBJ was still in high school). Heck, it's not even athletics. Take music. VH-1 or MTV has a top 100 songs of all time list, do you think they're gonna pick any song that doesn't have a video of theirs to go with it?
Tiger & Jack are both great. Too bad we can't see em play each other in their primes, with similar equipment, etc.