Tom Brokaw (search) began with a report on U.S. troops in Iraq. He ended the broadcast by saying farewell. After nearly 23 years in the "NBC Nightly News" (search) anchor chair, Brokaw reminded his viewers that "we've been through a lot together, through dark days and nights, and seasons of hope and joy.

"Whatever the story, I had only one objective: to get it right," he said Wednesday, declaring in a slightly quavering voice how he was "always mindful that your patience and attention didn't come with a lifetime warranty."

Brokaw, 64, is leaving "Nightly News" and daily journalism to pursue other interests, including more time on his Montana ranch. But he will still contribute to NBC News, doing at least three documentaries a year.

While Brokaw was saying his good-byes, Peter Jennings was praising him on ABC as "a competitor in the best sense, which in our trade means, when he beats us on a story, it is usually the result of enterprise."

On his CBS newscast, Dan Rather said, "For more than 30 years, I have known Tom as friend and competitor who has earned the respect of his audience, and his colleagues, myself included." Then to Brian Williams, Rather added, "Welcome to the neighborhood."

Williams, long groomed as Brokaw's successor, takes over "Nightly News" with Thursday's broadcast. He begins at the top of the ratings, where "Nightly News" has reigned since 1997.

Unveiled more than two years ago, the NBC transition plan was briefly upstaged last week by the surprise announcement that Rather would be departing "The CBS Evening News" anchor chair in March, after 24 years. (No successor to the 73-year-old Rather, who will report full-time for "60 Minutes," has yet been named.)

Those changes, after two decades of stability, will leave only Jennings among the old-timers.

Brokaw, a South Dakota native who joined NBC in 1966, was White House correspondent from 1973-76, encompassing the Watergate years. He anchored "Today" from 1976-81.

He began his "Nightly News" run in April 1982, sharing the anchor title with Roger Mudd. Then in September 1983, he emerged as solo anchor — just days after Jennings began soloing on ABC's "World News Tonight."

As Brokaw marked his 30th anniversary with NBC in 1996, he recalled the inevitable ups and downs at the network where he stuck it out and prospered.

"I never expected the waves would be quite as steep as they were," he admitted. "But even in the worst of times, it was better than anything I thought I'd ever have in life."

During a particularly turbulent stretch — in 1981, with NBC's prime-time ratings in a tailspin — Brokaw almost leaped to ABC News, whose new boss, Roone Arledge, had come courting.

"I came very, VERY close to going," Brokaw said. "So close that I went out to dinner with (wife) Meredith and said, `I'm gonna do this,' and she went to bed thinking it was a good idea. Then I sat up and drank some scotch and smoked a cigar and stared out the window for several hours."

At NBC nearly a quarter-century later, Brokaw signed off Wednesday by expressing gratitude to the viewers who had watched him through the years.

"Thanks for all that I have learned from you," he said. "That's been my richest reward."