Most sporting champions deserve our praise, some defy belief with their dominance, and a select few pull off feats that send our jaws tumbling towards the floor.
Whether or not he wins a seventh Tour de France before retiring in July, Lance Armstrong is in the final group.
But how does his achievement compare to those of six legendary solo sportsmen?
LANCE ARMSTRONG - SIX TOUR WINS
Armstrong is not considered the best cyclist of all time - that honour falls to Eddy Merckx, the "Cannibal" who devoured all rivals in the 1970s.
But by passing Merckx's five Tour wins, the American can lay claim to the sport's most significant record.
A Tour winner needs to combine climbing with time trial speed and endurance fitness that would put a marathon runner to shame. Armstrong has all three qualities in abundance.
The fact that the American bounced back from a cancer that almost killed him in 1996 makes his feat even more incredible.
MUHAMMAD ALI - THREE WORLD TITLES
The self-styled "greatest" had a brilliant boxing career and was the first man to become world heavyweight champion three times.
On each occasion, he showed remarkable resolve, stunning "unbeatable" champions Sonny Liston and George Foreman before winning back his title for a second time against Leon Spinks in 1978.
CARL LEWIS - NINE OLYMPIC GOLDS
With respect to long distance runners Paavo Nurmi and Emil Zatopek, Lewis is responsible for athletics' ultimate achievement.
Not only did the US sprinter emulate compatriot Jesse Owens' feat by winning four Olympic golds in 1984, he also won the long jump event at four-straight Games.
Lewis also added a silver to nine golds for a 10-medal haul.
MARK SPITZ - SEVEN GOLDS IN 1972
Swimmers tend to have more scope than athletes to win multiple medals at the Olympics - and Spitz took full advantage.
The American won a record-breaking seven golds at Munich in 1972 and added four further medals to that tally.
Spitz set an awe-inspiring mark - and Michael Phelps will need luck to go with his talent if he is to beat it in Athens.
JACK NICKLAUS - 18 MAJORS
Tiger Woods' ownership of all four majors in 2001 was a seminal moment in golf.
But a recent barren spell has shown just how difficult it is to keep winning the big prizes every year and has cast Nicklaus' 18 majors in impressive light.
As good as Tiger is, he may never eclipse the "Golden Bear".
PETE SAMPRAS - 14 GRAND SLAMS
Rod Laver may have won more Grand Slams had he not been banned from competing for six years after turning professional, but this should not detract from Sampras' trophy cabinet.
"Pistol Pete" went up against great players like Andre Agassi, Jim Courier and Boris Becker and generally beat them.
His only black mark is the lack of a French Open win.
MICHAEL SCHUMACHER - SIX F1 TITLES
Opinion is divided about whether Schumacher has surpassed the great Juan Manuel Fangio, but on paper, at least, he has.
The German already has six Formula One titles to match Armstrong and is certain to add another this year.
He also has more Grand Prix wins than anyone else and is fast closing in on Ayrton Senna's 65 pole positions.
SEVEN OF THE BEST TEAM STARS
Pele (football): 3 World Cups and 1,281 career goals
Don Bradman (cricket): Test career average of 99.94 runs
Babe Ruth (baseball): 714 homers, average of .342
Wayne Gretzky (NHL): 894 career goals with 1963 assists
Michael Jordan (NBA): Six titles, average of 30.1 points
Bill Russell (NBA): 11 titles in 13 NBA seasons
Steve Redgrave (rowing): Gold in five straight Olympics
The biggest compliment that can be paid to Armstrong is that his feat truly belongs in this exalted company.
But it is not the greatest.
On paper, Lewis' achievement is the most impressive, taking place as it did in modern times on the biggest sporting stage.
If pushed though, I would side with the effortless Ali.
He sprang two of the biggest shocks in sports history and reigned on-and-off for 16 years in the toughest arena of all.
YOUR REACTION (the debate is now closed):
NOTE: There has been massive support for Steve Regrave's five-straight Olympic golds - while that is a truly great feat, it was achieved as part of a team and is included in the "Team Stars" fact box.
Women were also not considered in order to keep the shortlist manageable, although the likes of Martina Navratilova, Steffi Graf and Fanny Blankers-Koen would be more than worthy.
For sustained domination in a speed endurance event, Lance wins it for me. Others have won and lost but seemingly nothing and no one can beat Lance.
Yes he has a team but so do his rivals.
Ultimately it's an individual event.
Try asking Ali to box 20 times in 3 weeks, Nicklaus to play 20 rounds in 3 weeks, Carl Lewis to compete day after day for three weeks, and win. Then ask them to repeat it every year for 6 years.
It's a bit of a quandrary, as I don't consider Armstrong to be the greatest cyclist of all time (Merckx has that wrapped up with his additional achievements away from the TdF) - but Lance's feats, particularly in light of the adversity he has faced, put him pretty much up at the top of the list.
A small mention of Merkx the greatest then? Wins the Giro, Tour and Worlds Championship in the same year!! And probably have won six Tours but for a Frenchman punching him. Certainly way above Ali in my humble opinion.
John Reynolds, Welwyn, UK
Even after 32 years, Mark Spitz's amazing 7 gold medals all in world record time at the 1972 Olympics remains the greatest solo athletic achievement of all time.
Marcella, Houston, Texas USA
The most dominant solo-sport champion currently is Takeru Kobayashi, who ate 53.5 hot dogs in 12 minutes in this year's Coney Island showdown.
Nothing comes close to Armstrong's achievement. It's not often I agree with President Bush but on this occasion I have no choice....AWESOME!!
Alistair McLean, Newcastle
Lance Armstrong is not the greatest cyclist in history, but his comeback from near-death is, in my mind, the greatest sporting achievement of our era.
Nick Richards, North Bend, OR, USA
While Armstrong's achievement is jaw dropping, I wouldn't rank him alongside the true solo champions that you list. He would not have won a single tour, and certainly would not have beaten Ulrich last year without his team.
I'm with Lance. Why do people always wheel out the "Ali the Greatest" bandwagon. Toughest arena of all?" You enter it for around 20 mins 2 or 3 times a year, and only reign "on and off." Let's get him on a push bike over the Alps for a couple of hundred miles!!!
My vote goes for Carl Lewis for the all time best solo athlete - he dominated the most competitive, core Olympic events.
Lance's record is incredible, but it was no solo sporting feat. Without the Domestiques on his team he simply couldn't do it.
Mikey McLean, Leicester, England
I am a great fan of cycling and the achievements of Lance but he didn't do it alone. He followed team-mates up hills before finishing the job.
Paul Thomas, York, England
In my mind I have to give it to the greatest alpine skier Ingemmar Stenmark of Sweden. His feat, 70 something world cups. He also got some Olympic and world medals and above all was a great role model.
The achievments of Al Oerter, four time Olympic Gold medalist and world record holder in discus in 1956,1960,1964, and 1968 must be included as one of the greatest sporting achievments of all time.
Washington, DC USA
Lance Armstrong's acheivement is on a par with Schumacher, Ali and Borg. These guys are the sort of role model all our kids should aspire to.
Ian Buckle, Blyth, Northumberland
I am proud of my fellow Texan, but my pick is Mark Spitz, who won basically everything available, or Jesse Owens, who, if nothing else, ruined the Fuhrer's day. There must be something in the water in Munich ...
Grant, Dallas, Texas, USA
I see a notable ommission from your list, the great wrestler Karelin, who was not even scored against for years.
I'm a big fan of Lance & his magnificent win BUT your list also left out the Siberian master Aleksandr Karelin who wrestled internationally for 13 years without being beaten!!!
Les, Virginia, US
Lance ranks alongside Ali as both have put in sustained efforts over a long time span. Their consistency and dedicated training have set them apart.I can't separate them, only applaud them.
David Mackenzie, Southampton
I think Carl Lewis achieved the greatest of all records when he won his ninth in Atlanta.
Eric Heiden who won ALL gold medals in Speed Skating, with world records in every race should definitely be on this list.
Edwin Moses winning the 400 meter hurdles 122 consecutive times from 1977-87 surely must be mentioned
Russell White, USA
What about Eric Heiden wining all the speed skating gold medals at a Winter Olympics? It wasn't quite the equivalent of a runner winning everything from the 100m to the marathon, but it came close.
Muhammad Ali's feat of becoming the first 3-time heavyweight champion is arguably one of the greatest sporting events of all time. None of the others listed expect Armstong come close.
Jim, Oxford England
Pete Sampras' dominance of world tennis has to be up there as one of the great sporting achievements - although I was shocked at your emmission of Bjorn Borg.
Michael Schumacher's achievement in winning 6 (soon to be 7) world crowns is so amazing as to be unbelieveable. However it seems he is not getting the credit he deserves. The ultimate professional sportsman of all time.
Surely the great Rocky Marciano deserves a mention. 49 fights undefeated rates highly in my opinion. Especially in a game as brutal as boxing.
Neil Dennehy, London
Yes, Lance Armstrong joins the stars alright! I's say he is SECOND - after Rocky Marciano (never defeated in 50 fights)! Golf and car-racing doesn't compare with the tough physical sports!!!!
Terence Gaffney, USA/ENGLAND
1996 Olympics 200m final - Michael Johnson. I have never seen a man move that fast. Pure blistering speed, it was phenomenal and awesome to watch.
Pete Sampras is my hero, but I have to admit lance Amstrong is the greatest solo sportsman of all times.
Bayingana Roger, Rwanda
Ed Moses - like Jhangir he did not lose for an increbile length if time in a purely individual event.
As far as I know, Ali, Spitz, Lewis, Nicklaus and Sampras didn't have a team around them willing to sacrifice their own ambitions to help them win. A great achievement doubtless, but individual? hardly.
Jason Tew, Manchester, England
As incredible as the achievements of Schumacher, Sampras and Lewis are I think that the fact that Armstrong survived cancer and then went on to win probably the toughest endurance event in the world puts him miles ahead
Michael, Grimsby, UK
As amazing as these people's achievements are how can you say that anyone is greater than Lance?
He was given a less than 5% chance of surviving the cancer, but beat it - he is truly matchless and I'll be happy to tell my children 'Lance Armstrong is my hero'.
Mat, Birmingham UK.
Jhangir Khan did not lose a squash match for five and a half years, winning 10 British Open titles.
Without an iota of doubt this is the best ever sporting feat in history. I only wish Armstrong stops now.
Ajmer Singh Bains, Punjab_India
I place Lance's accomplishment up there with Jesse Owens' four gold medals in Hitler's face.
Jay Margolis, Boynton Beach, FL
I can't believe you list Muhummand Ali but fail to mention Joe Louis. As a boxer, Louis had a far more impressive career. Ali's fame is a mix of his sporting acheivements and his political fame. Joe Louis was much more dominant in his time and at that time boxing was much more competitive.
John Semlak, Moscow, Russia
Undoubtly Michael Schumacher who is well on course to make it an incredible seven world driver championship. I am glad to to see history in the making.
Emile Heskey once controlled a ball, this achievement far outweighs any of the others you have mentioned!
Neil Irving, Barrow in Furness, England
We have just witnessed the 'mainman'. Lance Armstrong winning six tours. The others suggested have not got anywhere near to him in terms of fitness and his fight for life.
Rod Worrall, Plymouth U.K.
The greatest event in sports is world heavyweight boxing.
David Seaton, Madrid