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Once upon a TV season, a gay man named Will and a straight woman named Grace became unexpected sitcom darlings, challenging television's timidity toward homosexuality and buffing NBC's comedy crown.

Eight years after the debut of "Will & Grace," as the saga of the platonic pals draws to an end, gay characters and themes have emerged on other shows while struggling NBC — and TV in general — searches for the next hit sitcom.

While "Will & Grace" nudged cultural and comedic boundaries, however, its success came from sticking to the basics, according to those who made the series: Be funny and be good company.

"I think the humor of the program got people there and I think the relationship got people to stay," said Max Mutchnick, who created "Will & Grace" with writing partner David Kohan.

"David and I have always said a show creator's job is to put together a television show that consists of a world of people that you either want to be or you want to hang out with," Mutchnick said. "In the case of 'Will & Grace' it's about friendship. Everybody wants that kind of relationship in their lives. Gay, straight, black or white — that's second to it."

Veteran director James Burrows ("Cheers" and "Frasier" are among his many credits) has the clout to choose projects at will but made the unusual decision to stay for the entire 196-episode run as sole director and an executive producer.

Why? "It made me laugh every Tuesday night when we shot it in front of an audience," he said.

"Will & Grace" was part of NBC's powerful 1990s-born sitcom family that included "Seinfeld" and "Friends" and is the last of its generation to bow out, increasing the void for the ratings-challenged network.

Some critics have argued the show's quality ebbed, although cast and creators argue it's leaving with its head held high, citing its 15 Emmy nominations last year.

At its peak in the 2001-02 season, the series drew more than 17 million weekly viewers and was the eighth most-watched program. It's been watched by an average 7.8 million viewers in its final season, which concludes Thursday night.

"It's time go out," Burrows said. "America was not watching it like they used to watch it. I can't tell you why. It's as funny as it was ever funny."

The show's banter swooped between high sophistication and low bawdiness, turning tender when Will and Grace (Eric McCormack, Debra Messing) hit bumps in their friendship or love lives.

Add a couple of sidekicks who expertly stole the spotlight, Karen and the outrageously gay Jack, (Megan Mullally, Sean Hayes), and viewers were hooked.

"Eight years ago, a show with two gay guys would have seemed niche," said McCormack. "The opposite's happened. Kids watch it, old women watch it. Everyone wanted to know when Will was getting a boyfriend."

The character finally did, although the series played gay sexuality more for laughs — especially through the flamboyant Jack — than unabashed and open passion. That was largely left to Grace and her succession of lovers.

The show didn't "lead with its chin" when it began, said McCormack, explaining that the network had reservations about highlighting the homosexuality of Will, a serious-minded attorney.

"We could have easily made this a much more controversial show and maybe it would have been a hotter topic. But we might have ended after six episodes," he said.

Some gay viewers complained about Will's lack of romance as well as Jack's outrageous personality. Put his character in perspective, suggests Hayes.

"You have to represent every color of minorities in any presentation so as to explain to people, yes, there are people like this but there are other people like Will, who are probably more relevant in the gay community than the Jacks of the world," the actor said.

The series' rollicking humor wasn't offensive to one major gay rights organization.

"Without a doubt, 'Will & Grace' was groundbreaking," said Neil G. Giuliano, president of the Gay & Lesbian Alliance Against Defamation.

It proved that openly gay characters could be "embraced by the American public," he said, and put Will and Grace in the ranks of such classic and beloved TV characters as Lucy and Ricky of "I Love Lucy."

Most sitcom couples consist of husbands and wives engaged in low-level combat or attractive young singles who are warily courting and sparking, until exhausted scriptwriters finally force them to mate and the fun is over, a la "Moonlighting."

In the bittersweet case of Will and Grace, there was the chemistry of a great love in which they would never be lovers. That erased the problem of a post-liaison letdown but made it hard to envision a happy sitcom ending.

In the final, hourlong episode, written by creators Mutchnick and Kohan and airing 9 p.m. EDT Thursday, after a series retrospective at 8 p.m., Will and Grace test the strength of their bond.

Is there a chance the pregnant Grace might reconcile with husband Leo (Harry Connick Jr.), or does she remain loyal to Will, who stepped in when Grace was alone and offered to help raise her baby — whose college bill, Will joked, he already expected to foot.

Viewers will be satisfied with the conclusion, the actors said.

"It's daring and ambitious and more far-reaching than most finales go," McCormack said. "I think people will be quite surprised."

"I think 'Will & Grace' fans will be satisfied," Messing said. "Ultimately, it was done beautifully and it ties up loose ends for all of the characters in a way that is wonderful."

Burrows is largely unimpressed by the sitcoms that viewers will be left with. But he expects that to change, as it has in previous comedy lulls. So do Mutchnick and Kohan.

"I'll use my writing partner's words: Sitcoms are as obsolete as the next best idea," Mutchnick said.