A lot of people consider the idea that he is.
http://abcnews.go.com/Sports/story?id=2336758&page=1
...or Google "Tiger Woods greatest athlete"
Of course it's an objective thing so everyone will have an opinion, but I think there is a legitimate argument considering what he has accomplished.
my opinion is he is not the best athlete, he is the very best cpmpetitor who ever lived playing golf
I think "best athlete" would go to that individual who would win the most sports competitions overall, competing against the other "best" in their respective fields
no handicaps allowed either, that would defeat the purpose, boxers would not have to handcap for tug of war because of their weight, golfers would not have to handcap for dexterity in bowling
I don't think tiger would stand a chance against basketball players, field and track, gymnasts and even tennis players, I even doubt he would stand a chance against baseball players, he would possibly beat bowlers. equestrians and poker players, yes, both are considered "sports" (though not by me)
however, when competitor is so dominant they change the field of play to equalize the competition, that is one extraordinary competitor in that field
again, even though they have changed the field of play for tiger, I don't even think the man places in a competition of compiled sports with all respective greats competing in fields other then their expertise
my guess is even a non discript gymnast is a far superior athlete then tiger woods
as far as I am concerned, if you are not playing against the clock and there is no goal keeper, it is a competition not a sport
golf has neither