DENVER -- What started as Barackapalooza -- complete with throngs of ardent fans streaming into Invesco Field to listen to Stevie Wonder, Sheryl Crow and John Legend rock the stadium -- eventually morphed into the first official volley of the coming fall campaign.

Accepting his party's nomination before a nearly full stadium of some 75,000, Barack Obama, the first African American to lead a major party ticket, laid out a vision for the country and sought to allay concerns that his candicacy is more style over substance.

Given the sheer size of the audience, it was a tough thing to do, as the campaign sought to balance the spectacle to match the size of the event with the need to present their candidate as a tough but reasoned leader who connects with average Americans.

Crowds arrived beginning in the early afternoon, filing past parking lots full of satellite trucks and armed security. Even network news limos were stopped for search by bomb-sniffing dogs.

But if convention-goers were anxious at all, they hid it well under palpable enthusiasm and hopeful anticipation of the evening. Security lines moved faster than authorities predicted.

While warm-up acts included former VP Al Gore and Gov. Bill Richardson along with several ordinary Americans (apostate Republics among them) explaining why people should vote for Obama, it was the headliner himself the party faithful greeted with the longest and loudest ovation.

Speaking on a columned stage, and from a circular podium and runway that extended into the convention delegation, Obama wasted little time aiming his fire at his rival.

"I don't believe that John McCain doesn't care what is going on in the lives of Americans, I believe that he doesn't know."

Obama sought to directly address critics who say that he has not offered specifics, saying "let me spell out exactly" before he launched into plans for tax cuts, health care and energy independence.

One of his best lines hit McCain's perceived toughness on national security.

"John McCain likes to say he will follow Bin Laden to the gates of hell, but he won't even follow him to the cave where he lives."

And Obama all but embraced celebrity, when he outlined his own life story of humble origins. With a now infamous ad that compared Obama's fame to that of Paris Hilton and Britney Spears, McCain has sought to portray Obama as somewhat of a cult of personality.

"I don't know what kind of lives John McCain thinks celebrities lead, then this has been mine."

Obama brought the 70,000 attendees to their feet repeatedly, and each time digital cameras flashed by the hundreds, if not thousands. As he wrapped up, fireworks exploded into the cool evening air, delighting convention-goers.

But anticipation that the evening would end with some kind of superstar surprise performance never materialized. Instead, there was a closing benediction and House Speaker Nancy Pelosi calling the convention to a close.