Federer has tied Sampras, but never had a dominate set of opponents like Sampras. Chang, Agassi, Courier, Martin, Philipousis, Safin, McEnroe, etc. All Federer has really as a chief rival is Nadal. Besides, in his prime, Sampras would have kicked Federer's ass.

Tiger Woods is more impressive, about to eclipse all golf winners in a very short amount of time. Best ever at any sport, is Woods.

They are both the best of their generation. I think Sampras is just as good as Federer, but like Jack Nicklaus, the competition was better in prior generations. Sampras had many competitors that Federer does not have. Federer has only Nadal today. Tiger had almost no competition today. Jack had Arnie early on, then Miller and a slew of other great players. Plus the equipment they use today blows away the equipment and balls used just 10-15 years ago much less 30-40 years ago.

I would have to pick Roger though. He has to play on different surfaces - grass, clay and hard courts. Golf can have harder greens and taller roughs but it is still all grass.

woods is all hype, his is washed up and hasnt even tied Jack, CAN YOU SAY OVER RATED? its true

not to mention GOLF is not a SPORT its an activity, tennis is a sport, much different

This is a dumb comparison. Tennis is an infintely more demanding sport. It combines strength, technique, endurance and mental accuity. Golf includes two of these: Skill and mental accuity. The cardio-pulmonary fitness level required to play competitive tennis let alone professional tennis is extremely high. Hitting tennis shots after burning lots of calories with the accompanying muscle and mental fatigue is a tall order. On the other hand, you see players like Colin Montgomery and John Daly succeeding at golf. These guys have lots of skill, but they aren't world class physical athletes. Tiger has taken the fitness level to another level for golf, but it's still no match for tennis. Golf players of marginal strength and conditioning challenge and win. Players in their 40's challenge and win. Jack Nicklaus won his last Masters at 46. You will never, ever see a middle-aged tennis player in the top ranks. It's simply so unllikely it should effectively be considered impossible.

Federer. Tennis is far more demanding physically and harder to master. And when you hit a great golf shot, you get to keep it. But when you hit a great tennis shot, your opponent might neutralize it or even reply with a winner.

don't forget, in golf, the ball isn't moving when you hit it.

At this time, I'd have to go with Federer. I realize that Tiger has done what no one else has done and will likely end his career with about 24 major tournament wins, but due to golf's low requirments for physical strength, coordination and endurance, I just have a hard time taking it seriously.

Tennis is mostly a physical game. If you are better player, you almost always beat the other guy. You look at the major winners of the last 15 or so years (for as long as I remembered), it's almost always the top 5 ranked guys won it. It's very much like track and field or swimming, upset rarely happens. If you lined up Roger against, say Soderling, what's their head-to-head, 10-0 now and counting?

Golf is very different. It's mostly a finesse game, and a lot more factors come into play and affect the outcome - you mental state, weather, your teeing time, greens condition, luck of the bounce, which side your got off your bed, etc. You can play close to your A game and still lost, because some no-name or lesser name suddenly played out-of-his-mind and shot a course record. And if you look at the winners (major winners included), it's much easier for a lower ranked player to win (Todd Hamilton, Ben Curtis, anyone?). So I think to consistently winning golf tournament is extremely impressive. For instance, Tiger's match play record and play off record, that's just insane. It's much more than skills, it's the steel of mind.

I'm not saying Roger's feat is not impressive. But look at it this way. Let's say Roger finished with 16 majors, Pete has 14, and the all time list looks like (approximately) 16, 14, 13, 12, 11, 11 -- might be slightly inaccurate, but my point is that it's congested, so can't say Roger is that much better all time. But let's Tiger finished with say 20, then it's 20, 18 (Nicholas), 11, 9, 8, 8, something like that -- so Tiger and Nicolas are way ahead all time. I'd give the nod to Tiger.

Then again, if Roger goes on and on and finished with 20 majors himself, then I might consider a switch...

I'll offer one more argument. The best golf tournament to compare with a tennis championship is the Accenture match play, when the top 64 ranked players get together and play 18 hole match play knockout. In tennis, how many times you see the #1 get bounced on the first day? It's much more predicatable in tennis, when there's an established pecking order...

But in golf? The ranking means practically nothing, that's how closely matched for the top 64 players, and how fickle the game is. It's basically a toss-up for each round, and the results can back it up. It's virtually impossible to predict - except for Tiger (but only to a certain degree), who won it 3 times and finished runner-up another time in 7 or 8 tries, -- and also got knocked out once on the first day by Peter O'Malley (a complete no-name Aussie), and knocked-out by Nick O'Hearn twice (hardly a big name, another Aussie). And go check the record of Michelson, Vijay, Ernie, etc. it's borderline shocking (rarely passed the 2nd round). THAT WILL NEVER HAPPEND IN TENNIS, not even close.

So again back to my point that winning golf tournament consistently is more difficult...

There maybe 80 other competitors in golf but no one plays directly against the other like in tennis where the ball has to be returned.  I like Tiger's play very much but he too has those moments of cockiness as jeffden says of Roger.  Like you don't show your fist up when you're so pumped of the win.  I'm just saying...

Since we are seeing Fed and Tiger being compared and we also see Fed and Sampras being compared why dont we compare Sampras with Tiger or Tiger and Jack. The best one to examine is Pistol Pete and the Bear. Sort that one out and it may change and inform the previous comparisons.

So waddya think: Pete or Jack? Neither Tennis nor Golf as competitions have changed to the degree that a comparison would not be valid