Eddy Merckx >>>>> everybody else in the sport. He was a freak, took home 5 Tours (would have been six if some madman didn't run up[ and punch him the gut pretty bad), took home the Giro as many times as well, and missed a Tour to win the Tour of Spain (Vuelta a Espana) and Giro (back then the Vuelta was held early in the year while the Giro has always been held in May), throw in being three times the World Champion, took home 7 Milan-San Remo classics (about 294 km) and virtually all of the classics and set a World Hour Record in Mexico City as well (
this site is useful).
The next one is Bernard Hinualt (last Frenchman to win the race 21 years ago) who was dominant in his era as well. What he said went, you did not dare get on the wrong side of the Badger. In one Tour he ordered everybody to take it easy so his team-mate could recover, so one rider attacked, and Hinualt enraged went off the front to chase him down and to bring him back to main bunch as if to leach him a lesson.
In a important lead-up race to the Tour - the Dauphine Libere Hinualt turned up in 1981 with the intention of lowering his rivals slef esteem forver. On Stage five he won the stage to Lyon, and then Alps he cracked his knuckles by winning smashing everybody apart in stage 6. On stage 7 he went on the attack with another rider and won that stage. By the next stage he told everybody to take it easy, but Spanish rider Mariano Martinez attacked, and Hinault enraged went off the front went over the climb alone, and was even caught by ten other riders by still won the sprint for the line. He also was World Champ and did the Giro - Tour double and he won his fair share of classics as well.
Armstrong himself was only concerned about the Tour and all of his workers all gave up their own ambitions to help him win. To put it this way in 2005, the year of his seventh victory, was the only time somebody other then him won a stage. Armstrong never won the Giro (Often the course is a lot harder then Tour route), in fact he never took part. Then again the Tour is the only race that registers on the American non cycling rader and it has got him Letterman, Opreah, and even friends with George W. Bush (and for the record he does disagree with some of Bush's policies), so I guess you can see the logic in trying to win that race then try and pick up a Tour of Flanders, or the Giro when they don't mean diddly squat back home in the States instead of a Tour victory.
That said pre-cancer he was pretty good rider in his own right, two Tour stage wins and being World Champion at age 21 (youngest to do so).
