NEW YORK - The death of Peter Jennings means an era in television news has ended with stunning swiftness, giving broadcasters the challenge of reimagining the nightly news in an age of instant Internet updates.

Jennings, 67, died Sunday at his Manhattan home. He hadn't been seen by viewers of ABC's "World News Tonight" since announcing in April he had lung cancer.

For more than 20 years, many American television viewers learned the day's news at the dinner hour from either Jennings, NBC's Tom Brokaw and CBS's Dan Rather - covering the Reagan era, communism's fall, O.J. Simpson and the Sept. 11 terrorist attacks.

The triumvirate held steady as the world of news changed around them, driven by the spread of cable and the Internet. Today, people can get news headlines simply by flipping open their cell phones.

Brokaw, 65, retired from the "Nightly News" in November, and Rather, 73, signed off in March. With Jennings gone, the days of name-brand anchors serving as the public face of their news networks may be disappearing as well.

"It's a cruel twist of fate in that Jennings was suddenly going to have the network (evening) news to himself after 20 years of long service," said William Lord, a Boston University journalism professor and one of Jennings' producers in the 1980s. "This was going to be Peter's time to reclaim that No. 1 ranking."

Jennings, a former smoker, spoke bravely of keeping up with work when he revealed his cancer diagnosis on April 5. But he wasn't seen at ABC's Manhattan offices after late May.

Charles Gibson and Elizabeth Vargas filled in for him at "World News Tonight," a role both will continue indefinitely. ABC wasn't talking about the broadcast's future on Monday.

"There will be a time to discuss that," ABC News spokesman Jeffrey Schneider said. "This is not that time. When we emerge from this difficult time and are prepared to say something, we will."

It's almost certain the next "World News Tonight" anchor will come from within ABC News.

Gibson, 62, is a solid contender, familiar to ABC viewers as the longtime anchor of "Good Morning America." He anchored ABC's live coverage of Pope Benedict XVI's selection and the space shuttle Discovery's takeoff last month.

However, moving Gibson into that role would take him off "Good Morning America," which has been surging in the ratings and giving NBC's "Today" its first serious fight in a decade. Leaving him in the morning would signal the increased importance of that time slot to news divisions; it's already a big profit center.

Vargas, 42, lacks Gibson's experience but could attract some younger viewers. The evening news, a tradition born at a time when evening newspapers were important, has one of television's oldest audiences.

ABC's anchor bench also includes people like Bob Woodruff, John Donvan, George Stephanopoulos, Dan Harris and Cynthia McFadden - all of whom have also tested as potential "Nightline" anchors for when Ted Koppel leaves at the end of the year.

One approach could be to give Vargas the "World News Tonight" job and have Gibson anchor many of the big breaking stories. On CBS, evening news substitute anchor Bob Schieffer has occasionally given way to John Roberts and others on big stories.

ABC's rivals have shown sharply different approaches in their transitions to new anchors. NBC planned the switch from Brokaw to Brian Williams with machinelike efficiency, and Williams has kept Brokaw's top spot in the ratings, with nearly 10 million people tuning in each weeknight.

CBS appointed Schieffer as Rather's temporary replacement for a few months while promising "revolutionary" change at the third-ranked newscast. But a few months has now become six, and no permanent plan has been announced.

What the network has announced are detailed plans to turn its Web site into a 24-hour broadband service with dedicated video content.

Jennings' death, together with the departures of Brokaw and Rather, means "a whole bunch of people are going to be writing obits about the network evening newscasts," said Joseph Angotti, a former NBC News producer and lecturer at Monmouth College in Illinois.

"And, as they have been in the past 30 years, they're premature," Angotti said.

With many of journalism's trends pointing away from the evening news, the three networks still draw more than 25 million viewers each night combined. That's down from about 34 million a decade ago, according to Nielsen Media Research.

Jennings had five decades of longevity in network news that might never be matched: He anchored ABC's evening news briefly in the 1960s, came back in the 1970s, then became the face of ABC News for good in the 1980s.

The Canadian-born Jennings' father, Charles Jennings, was a famous anchorman back home. His son had his first broadcasting job, a radio show in Ottawa, at age 9.

"Peter was born to be an anchor," Brokaw said on NBC's "Today" show on Monday.

Jennings could speak smoothly and authoritatively on many subjects - the best ad-libber in the business, colleague Barbara Walters said. The former London correspondent had a suave, debonair appeal; Brokaw joked about wearing an ascot in tribute on Monday.

Beneath the outside eloquence "beat the heart of a fierce competitor," Rather said on "Good Morning America."

A high school dropout, Jennings was restlessly curious - an attitude Walters said was born of a journalist's natural skepticism and a hint of insecurity.

After his brief, unsuccessful stint as ABC evening news anchor in the 1960s, Jennings became one of a three-person team to anchor the new "World News Tonight" in 1978. The job became his alone in 1983.

He marked his final birthday on July 29, an occasion his ABC News colleagues noted by sending a plane with a birthday banner over his home in Long Island, N.Y. A jazz lover, Jennings loved to host birthday concerts with friends at his home.

This year, too sick to celebrate in his traditional manner, ABC colleagues sent a small jazz group into his home to perform.