I like the idea of comparing age and how or when people took up the game. I'll use my Father in law as an example because he like so many average golfers never played or took up golf until he retired which happened to be right at the height of Tiger's dominance. My Father in law is(not quite as much since the fire hydrant incident) a huge Tiger fan. He never watched or followed golf back in the 60's/70's and although he's plenty old enough, never watched Nicklaus play. So I'm not surprised to see a lot of votes for Tiger from the over 35 crowd, it's who was winning as they got older and had more time/money to get into golf. It's no different in any other sport, the Patriots, Steelers, or Cowboys win 3 or 4 Superbowls and they instantly have fans from coast to coast selling jerseys like crazy!
I'm 48 and voted for Nicklaus, much like the 35 and under voted for Tiger. Nicklaus was who I grew up watching and idolizing like many of the junior players of that era that golf was their primary sport. I know people like to get all fired up about who was the greatest ever but I think it's more relevant to break it down into era's. Not just because the equipment was different but also because the world, travel, logistics, and standards of greatness were all different within each era.
Golf just like the rest of the world has gotten bigger, better(debatable), faster over the last +100 years which equates to each era having a different set of standards as to what was considered greatness! When Nicklaus got to 15 Majors(4 ahead of Hagen) most people that really followed golf thought that might stand for a 100 years. When he added 2 more in 1980 it was thought it may stand forever, yet 34 years later here we are with a guy within 4 that may or may not get there.
As far as Jack v.s. Tiger I will say Tiger had a huge advantage over Jack in popularity because Jack had to follow and dethrone "The King" Arnold Palmer. When I got into golf as a kid Jack was at his height and many people my fathers age were still huge Palmer fans and didn't give Jack a lot of love for taking down their guy! As for Tiger, there was no "Big Dog" to take down when he turned pro but he did spawn a whole generation of young guns that are now lighting it up, which outside of whether Tiger catches Jack or not may be Tiger's greatest legacy. He took golf into the era we are in now and earned his spot at the table as one of the greatest ever!
I guess it's fun to debate the greatest ever but I like to enjoy the accomplishments of each era so for myself it's a 5-way tie between Young Tom Morris, Walter Hagen, Ben Hogan, Jack Nicklaus, and Tiger Woods.