[ShawTaylor]

It's Tiger, easy.
Not only has Tiger won ALL the 4 slams in 12 months for a "Tiger Slam", he was won every single grand slam at least twice.
Federer hasn't even come close to wining the French Open.
Lemme know when Federer actually wins all 4 slams, let alone win them in 12 months.

[battlegearboat]

You're preaching to the choir.

[Alberta's Child]

That's not a valid comparison, since the four tennis Grand Slam events are played on different court surfaces.

If Tiger Woods had won all of the major golf tournaments in one year, and they were played on surfaces as widely varied as these . . .

1. Short Grass
2. Tall Grass
3. Sand
4. Concrete

. . . then you might have a point.

It's almost impossible for a male tennis player to win all four Grand Slam events anymore (even the legendary Bjorn Borg couldn't do it) -- because the skills required to win on each surface can vary widely.

[Wyatt's Torch]

And those feats are far more rare in golf than in tennis. It is much more difficult to be "on" in golf all the time than in tennis. There is far less margin of error in golf as well. What Tiger has done in golf is simply amazing.

[Tallguy]

Tough one, but I have to go with Federer. It's really hard to win tournaments when you are playing a series of head-to-head matches. 1 bad day, or 1 opponent who's game is made to beat you, and you're out. Tiger often survives a bad round to win a tournament.

I'm not criticizing Tiger. Golf requires a mental toughness that is comparable to Chess -- plus you got to hit the shot.