Would we, in our lifetimes, have possibly seen sporting heroes, who might be considered to be the best ‘ever’ in their respective sports??
Lets try and pick some names.
Michael Jordan in basketball. I presume this will go through unanimously!
Schumacher. I am not much of a racing fan, but having seen the following, and the results he managed to notch up, maybe he qualifies.
Tiger Woods. Well, in terms of sheer numbers, he may have a distance to cover, to catch up with the big heroes of yesteryears, but he has many playing years left, and he seems to be at top form, still, so there is fair chance that he will emerge on top, by the time he is done. And there is enough evidence of his abilities, till date, to believe that he can justify the tag of being ‘best ever’!
Federer. Here is where I expect the most debate to come in. Sure, there was Samparas. And many others like Laver and Borg, and what not. But again, like Woods, at a relatively early stage of his career, Federer has shown an awesome game and dominance that makes one believe that he can lay claim to that position of being best ever. Okay, he needs to continue his performance at this level, for a few more years. But he is definitely out there.
Amongst the popular sports, these are the names that I could think of.
No, sorry, it does not work in cricket. First of all, there was Bradman. So….!
Also, even in present crop of greats, it is tough to make a call – Sachin or Lara or Ponting, etc. So we will not elevate any of them to anything even close to the ‘best ever’ levels!
Random Musings 
It is so hard to determine the best ever. I think it is better to say best of our generation. And in that case, certainly ALL the names you listed qualify.
And of course, we have to talk about what makes someone ‘the best’. What are you going by? Spectator viewpoint? Match-saving/Match-winning abilities? Averages? Statistics? Remember, the game (any sport) was much different earlier than it is now. To hit a 140kmph ace in tennis is almost a no-brainer now, for example.
Based on any or all of these, the names may or may not make it.
USC Trojan:
Yes, its never easy to compare players across generations. Technology, surfaces, etc. all change. So this exercise, at best, is a hypothetical one. Still from an audience’s perspective, if we have to compare the quality of a person’s game, not just with respect to earlier players, but also with respect to his / her contemporaries, and when we find a huge dominance, someone being truly streets ahead, that is when we can venture with statements like ‘best ever’.
The ‘best of our generation’ is not that big, really.
@spm: Don’t forget to add Martina Navratilova, Steffi Graf and Pele …
USC Trojan:
Pele, I guess, must make it. I am not such a great soccer fan, and Pele was also kind of an earlier generation, so saw very little of him. But from what we read and hear, I suppose he was a magician with the soccer ball, and he should be in that list.
As should Martina, who makes the cut, in women’s tennis, definitely.
Graf, I don’t know. Obviously she was awesome, but would I put her in the same league as Martina? Guess not.
Other names (not personally familiar to that extent) that could make the cut, are Sergei Bubka and Armstrong, perhaps.