(CNN) -- There was no pretense with David Letterman, and the response to his retirement has been just as honest.
From President Obama to Dave's late-night peers, the veteran host of CBS' "The Late Show" has left his fans devastated with his announcement that he plans to hang it up in 2015.
"There are more than 10 reasons #DavidLetterman will be missed," the President posted to his Twitter account Thursday, with a photo of himself laughing it up with Letterman.
"David @Letterman is the best there is and ever was," ABC's Jimmy Kimmel chimed in Thursday.
"There's a tear under the CBS eye!" said Arsenio Hall. "David Letterman - Simply The Best!!!"
"It's been 31 incredible years," said Ellen DeGeneres. "Television won't be the same without you, Dave."
There's a tear under the CBS eye! David Letterman - Simply The Best!!!— Arsenio Hall (@ArsenioHall) April 3, 2014
On Thursday's "Late Show," Letterman said that while everything's been great, he's simply ready to retire.
"We don't have the timing of this precisely down," he said, "but sometime in the near distant future, 2015, for the love of God, Paul and I will be wrapping things up and taking a hike."
Letterman broke the mold for not just Late Night, but TV itself. He's a vanguard- his influence is seen all over the dial today. What a run!— Andy Cohen (@Andy) April 3, 2014
Mr. Letterman, you have always been the best. I've had more fun on your show and you've been a class guy all the way. Enjoy ur final days.— jason alexander (@IJasonAlexander) April 3, 2014
David Letterman announces that he will retire next year. CBS frantically looking for someone named Jimmy.— Albert Brooks (@AlbertBrooks) April 3, 2014
On his own late night show, NBC's Seth Meyers took a moment to recognize Letterman's influence.
"I grew up on David Letterman," Meyers, who just recently took over "Late Night," told his audience. "I was a little too young for (Johnny) Carson, I discovered Carson in later years online and watching videos that way. But Letterman for me was a show that you had a cool uncle, or one of your friends had a cool older brother that told you to watch. ... If it wasn't for David Letterman, this show wouldn't exist. If it wasn't for David Letterman, I wouldn't be here."
Since Letterman's announcement, the conversation has inevitably turned to who could replace him -- although Esquire magazine believes that may be impossible.
But CBS, presumably, will have to find someone to take on Jimmy Fallon and NBC's "Tonight Show" at 11:30. One obvious option would be to bump CBS' "Late Late Show" host Craig Ferguson up an hour, and mimic what NBC's done with the handoff of "The Tonight Show."
There's also interesting competition for Letterman's seat on cable, where Stephen Colbert and Jon Stewart have proven that they can draw a young audience and hold it. And now that Chelsea Handler is reportedly ending her E! late night talk show, "Chelsea Lately" -- hers is another name floating amid the speculation, along with those of other funny ladies like Ellen DeGeneres and Amy Poehler.
But the predictions haven't been limited to talk show hosts, as the Twitterverse has erupted with suggestions that comics like Louis C.K. or Jerry Seinfeld take over. The name of a different kind of entertainer showed up in The New York Times' take: Neil Patrick Harris.
And there might be room for the Ghost of Jack Paar -- a combustible conversationalist who brings the "talk" back to "talk show" -- or some YouTube talent out there, yet unknown, who gets a "Rocky"-like chance at stardom.
Lena Dunham, for one, is rooting for CBS to be the network that breaks up late night's boys club.
"I love Letterman but I am really excited about what this could mean for the diversification of late night," she tweeted, although she added that she'll "obvi ... miss Letterman and his gorgeous tooth scenario/general brilliance."
Comedic actor Billy Eichner can see it now, as he promotes another actress, an Emmy nominee for "Nurse Jackie": "Late Show with Merritt Wever."
CNN's Todd Leopold contributed to this report.