Countdown host Keith Olbermann speaks as his one-time producer and now boss, Phil Griffin, looks on.

An MSNBC landmark was celebrated last night at the Landmarc restaurant at Time Warner Center, home of CNN. (As one insider told TVNewser, "let's just say, there were other locations available.") A thumb in the eye for a competitor, but a landmark for the MSNBC host. In a few months, Keith Olbermann will mark 5 1/2 years at the network, the longest he's spent at one place in his career. He told the crowd he was ready to leave MSNBC last year, "because that's what I always did." He was convinced to stay, with a deal that keeps him until 2011.

MSNBC exec-in-charge Phil Griffin, who's known Olbermann for 27 years and once produced for him when they worked at CNN says "Keith got TV from day one. He revolutionized sports and now he's revolutionizing news."

NBCU CEO Jeff Zucker told the crowd of Countdown staffers, contributors and current & former NBC executives that Countdown is "one of the true signature brands of the company." Not just MSNBC, but the entire company, Zucker said. NBC News president Steve Capus called the show "must see TV," adding "imagine if Countdown were around during Watergate..." "...or that Lewinsky story," Olbermann offered.

It was that Lewinsky story that put an end to Olbermann's first run at MSNBC. He said he was wooed back to the peacock by NBC Sports & Olympics chairman Dick Ebersol. The original deal called for hosting "three shows, filling in for the late Jerry Nachman." Five years later, he's still there. Said Olbermann, "I hope we're standing here in five years."

Who else showed up and pictures, after the jump...

In addition to NBCU execs Zucker and Capus, former MSNBC president Erik Sorenson was on hand, as was former NBC News president Neal Shapiro. Nightly News anchor Brian Williams dropped in, as did his EP Alex Wallace; other MSNBC anchors including Alex Witt and Tamron Hall stopped by; Lester Holt of Weekend Today and Nightly News was there; and the Countdown regulars, Jonathan Alter, Howard Fineman, Craig Crawford, Richard Wolffe and Maria Milito.

NBCU president & CEO Jeff Zucker, NBC SVP Phil Griffin and Keith Olbermann.

Countdown contributors Maria Milito and Richard Wolffe bookend show booker Amy Shuster.

Countdown EP Izzy Povich, MSNBC VP Bill Wolff, his wife, NPR's Alison Stewart (due to give birth in three weeks) and Countdown senior producer Greg Kordick.

Olbermann and documentarian Ken Burns.

The entrances to the Time Warner Center (home of CNN) included these mall ads advising of the Countdown party.

NBC News president Steve Capus, SVP of Communications Allison Gollust, and Nightly news anchor Brian Williams.

Wolffe, Olbermann and NBC Sports' Bob Costas.