Paris was up first and French President Jacques Chirac took to the stage on Wednesday to tell the International Olympic Committee (IOC) delegates they could put their trust in his city and his people.
"I shall vouch for this, you can put your trust in France, you can trust the French, you can trust us," Chirac said at the Raffles City Convention Centre, the venue for the vote.
Paris entered the final day of the much-anticipated contest to host the games as frontrunners alongside London, with New York, Madrid and Moscow believed to be outsiders.
"Nearly all the members have already made up their mind and it has come down to Paris and London," one senior IOC member said on Tuesday.
Chirac's presence in Singapore gave a dramatic boost to the Paris bid, with his short speech the centrepiece of the city's hour-long closing presentation that featured a slick video clip made by celebrated filmmaker Luc Besson.
"The heart of Paris and the heart of France are beating in unison in the hope of becoming Olympic ground in 2012," Chirac said, adding that he was making the appeal with "emotion and passion".
France promised the country's
devotion if it won the bid
Chirac promised the full devotion of everyone in France, should Paris win the games.
"Paris's bid is that of France: A united, enthusiastic France who is rallying nationwide to host the games," he said.
New York glitz
New York offered all the glitz and power the city is famous for in its presentation, which followed Paris, with a formidable lineup of sports champions, Hollywood stars and political leaders appearing on video and in person.
To the strains of Frank Sinatra's classic song, "New York, New York", the Steven Spielberg-produced video component of the presentation featured US President George Bush and his predecessor Bill Clinton.
In a short speech on the video, Bush promised his and the government's "total" commitment.
"The United States government is ready to do whatever it takes to work with you to make sure everyone has a great experience ... in New York," Bush said.
Repeating variations of the slogan: "Our city is yours", video cameo appearances were made by actors Robert De Niro, Billy Crystal and Meryl Streep.
Others who appeared to chant the "our city is yours" punchline included real estate mogul Donald Trump, basketball player Magic Johnston, boxer Sugar Ray Leonard, cycling king Lance Armstrong and tennis player Serena Williams.
In the audience as part of the New York delegation in Singapore were boxing great Muhammad Ali, former secretary of state Henry Kissinger and Australian swimming champion Ian Thorpe.
Boxing legend Muhammad Ali ( L)
was in New York's delegation
Moscow followed New York, and Russian President Vladimir Putin made an appearance via video to give his "absolute endorsement" of the city's bid, although the presentation was more low-key.
London and Madrid were due to give their presentations in the afternoon, with the IOC delegates scheduled to vote on which city will host the games at 7.30pm-8pm (1130-1200 GMT).
Ninety-nine of the 115 eligible delegates are expected to vote in the first round, with those from the candidate cities and IOC president Jacques Rogge excluded.
If a city does not secure a majority, the candidate with the least number of votes is eliminated.
The eliminated city's delegates are then allowed to vote in the next round and the process is repeated until a city secures a simple majority.