hard to answer, so here comes the long-ass post (this is not a quarrel with anyone's selections, but actually it's completely self-indulgent)
if being dominant at a skill matters then you could pick any number of skill athletes more dominant than Tiger Woods.
Check out Steffi Graf's numbers, she not only won an actual Grand Slam (not a Tiger Slam) but also a Gold medal the same year. 1988. She beat Zvereva (sp?) 6-0, 6-0 in the French final in about 37 minutes or some shit. Unreal. Yes, that is only one year of course.
So let's go to majors. From 1987-1999 she won 22 major titles. Tiger has been playing pro for 9 years and has 9 majors. Don't get me wrong, Tiger is a bad-ass, I am just making a point.
He's an easy choice and a good one, but he's also doing something considerably less "athletic" than tennis.
If Steffi Graf looked like Sharapova or Kournikova and she were an American or even spoke better English at the time, she'd have been the biggest name in all of sports. Is my love for Steffi showing? Can't help it.
I am not arguing with anybody, I'm just using this as an excuse to pimp Steffi.
What makes Michael Jordan a great athlete, because he can dunk from the free throw line or because he can put a rubber ball through a metal hoop on a ten foot pole. Part of that is the skill, so let's talk athletics, there is no way he was comparatively MORE athleltic than Julius Erving, who also dunked from the free throw line. Is it because he has championships?
if having championships and being a winner matters, then you couldn't pick Michael Jordan over Bill Russell who had 3 more titles than MJ. You'd also have to look at Terry Bradshaw who won just as many Super Bowls as Joe Montana. But then again, we are back to skill. Because while Montana, Marino, Unitas and Elway are often considered the best 4 Quarterbacks ever, they are essentially just good at a certain skill that requires athleticism.
To be good at many skills that require athleticism, now we are getting somewhere, but still what differentiates one skill from another, what seperates the discus from throwing fastballs? I guess it's difficulty, which is hard to measure. You could easily argue that the hardest thing to do in sports, team sports generally American is to hit a baseball. But that doesn't take into consideration many other odd skills that could be considered more difficult, maybe archery, who knows??
What is the point? Well besides boredom rambling, I think any of these lists is so completely subjective that it's really hard to argue with other people's selections, unless it's apples to apples.
As an American, who primarily likes American sports, as well as tennis and golf, and several olympic sports, I don't really have a definitive top 5. My favorite football player of all time is Joe MOntana, I could write a 200 word dissertation on why I think he's the best quarterback of all time, but that doesn't really make sense if I am comparing him to say, Jack Nicklaus or Jimmy Connors.
so by the sports I enjoy in particular, last 20 yrs: (top of my head)
Baseball
1-Roger Clemens
2-Barry Bonds
3-Ken Griffey Jr.
4-Tony Gwynn
5-?? tough, maybe Ripken for sentimental reasons
Basketball
1-MJ
2-Magic
3-Bird
4-Barkley
5-Olajuwon
Football
1-Jerry Rice
2-Barry Sanders
3-Joe Montana
John Elway
5-Lawrence Taylor
Golf
1-Tiger
2-Nick Faldo
3-Phil Mickelson
4-Greg Norman
5-Ernie Els
Tennis
1-Steffi Graf (maybe the most dominant I've ever seen any sport)
2-Pete Sampras
3-Andre Agassi
4-Roger Federer
5-Navratilova, hell she was still damn good after '85
sydney almost went into meltdown when it was hinted he might slink his nasty arse up our way 
The most successful women's hockey team ever.
