
The British team chose the headquarters of their engine partners Mercedes-Benz in Stuttgart to launch the MP4-23 - and said it was putting the turbulence of the 2007 season and the espionage affair behind them.
"This is a year of forward thinking for us, we are looking forward," team boss Ron Dennis said.
"We are not spending any time dwelling on the past. We are intent with everyone in the company in producing a competitive racing car, a car that is constantly evolving and will look radically different by the time we get to the first Grand Prix."
Hamilton said the car launch was "the coolest present you could ever hope for" and said he felt "stronger than 2007" when he was narrowly pipped to the world title in his debut F1 year by Ferrari's Kimi Raikkonen of Finland.
Like the new Ferrari launched Sunday, the MP4-23 features a longer wheelbase than last year's car in an effort to compensate for the banning of traction control and other electronic driver aids by the sport's governing body FIA.
The experience of last year, when the team was fined 100 million dollars and barred from the constructors' championship, was not an issue at the presentation.
However the team has frozen development of certain aspects of the car following last year's spying scandal.
McLaren chief executive Martin Whitmarsh said the car was faster than the version that ran in the last race of 2007 in Brazil.
"We are confident, based upon the simulation and analysis which has been an integral part of the development process, that the MP4-23 represents a step forward," he said.
"Of course we will continue to develop the car from now until the first race in Australia and see whether we have done enough to be at the level where we want to compete this coming season."
Hamilton said he did not feel as if were the leading driver in the team, with team-mate Heikki Kovalainen of Finland as an equal.
He predicted the biggest rivals in the new season, beginning in Australia on March 16, would be Raikkonen and Ferrari team-mate Felipe Massa, his own team-mate Kovalainen, and last year's McLaren team-mate Fernado Alonso of Spain, now in a Renault.
Test driver Pedro de la Rosa will give the car a first run at Jerez, Spain on Wednesday.