Armstrong, the 31-year-old team leader of US Postal, became the fifth rider to have won the race five times, equalling the record of Spain's Miguel Indurain who won the race five times consecutively between 1991-95.
"I'm tired but happy," said the Texan on the Champs-Elysees. "This was the most difficult of all my five wins, but I'll definitely be back next year to try for my sixth."
Germany's 1997 Tour winner Jan Ullrich came second overall on the race, the 29-year-old Bianchi team leader finishing 1min 01sec behind Armstrong after giving his American rival a scare halfway through the race.
"I am very emotional about it," said the German who has now finished second on five occasions. "It is the sixth time that I have had this feeling. It was really a superb Tour this year and after so many dark years for me, this has been a great comeback."
Telekom rider Alexandre Vinokourov became the first Kazakh rider to finish on the Tour de France podium, the 29-year-old finishing third at 4:14. "I'm happy to get on the podium, although I didn't expect to do it this year," said Vinokourov, the winner of the race's ninth stage to Gap on the day that Armstrong narrowly avoided the fatal crash of Spanish rival Joseba Beloki.
Vinokourov, the winner this season of the Tour of Switzerland, his second straight Paris-Nice and the Amstel Gold Race, also picked up the prize for the race's most aggressive rider.
Frenchman Jean Patrick Nazon, who wore the yellow jersey for a day during the race, snatched the last day's stage on the Champs-Elysees ahead of Baden Cooke and Robbie McEwen who crossed the finish line shoulder to shoulder in the battle of the sprinters.
French cycling legend Bernard Hinault, one of the five riders to have won the Tour de France five times, has hailed this year's eventful centenary edition as exceptional.
Hinault, the last Frenchman to win the race in 1985, said the increased challenge to Lance Armstrong's yellow jersey this year doesn't mean the 31-year-old American five-time winner is on the wane.
"This year's race has been exceptional on all levels as a competition and as a spectacle but also the way it has been organised.
"It's been one big party and there was suspense right up to the end because the adverse weather conditions meant that anything could have happened," said Hinault, who is optimistic for the future of French cycling but said that Armstrong's closest win in the race so far does not necessarily mean he's on the decline.
"It's hard to say. He's definitely had a harder time than he normally does, although he came right back into it at the end with a great time trial and at Luz-Ardiden (where Armstrong won after a dramatic crash). Will he be there next year? I don't know. Maybe he won't be at the start of the Tour at all next year," added Hinault.
In the meantime, a Tour de France rider has failed a dope test for the performance enhancing drug erythropoietin (EPO), Tour deputy director Daniel Baal said last night. Baal did not name the rider and said analysis on the B sample of the urine test was underway.
"I can confirm that a Tour rider has failed a dope test for EPO," Baal said. "We don't know who he is but we can confirm he is not a stage winner or one of the leading riders in the overall standings," Baal added.
The Tour deputy director said the rider had asked for a second test to be undertaken.
"Results on the B sample should be announced some time next week," Baal said.
The test took place halfway through the Tour, "in Marseille or Toulouse", Baal added.