Many of the later Pretty Cure movies involve the heroes having adventures in various Sugar Bowls, like the Kingdom of Sweets. In addition to that, the alternate worlds that the girls have to save in each season are inhabited by ridiculously cute critters.
Arguably, most Hayao Miyazaki is in essence this. In one way or another, the world is almost absurdly nice to nice people. It's been observed that given the evolutionary forces of Miyazaki's words, the world should be populated entirely by nice people well before the invention of fire.
Jewel Land in Jewelpet Twinkle is very much a sugar bowl. The only thing that's evil in it is a book of forbidden spells locked away IN SPACE on a rock orbiting the planet.
The mysterious star in Fushigiboshi No Futago Hime. About the worst thing that can happen is hurting someone's feelings.
Comic Book
The French comic series Les Womoks, a sci-fi parody series about a bunch of sub-par space troopers, features the Albon, an alien Sugar Bowl civilization of Ridiculously Cute Critters. They seldom come out of encounters with the Womoks without getting the business end of an explosion, yet somehow never lose their ludicrously optimistic view of life, even after their world gets invaded by the setting's Proud Warrior Race badguys. And after their homeworld gets blown to pieces in the following liberation? They happily live on the resulting Floating Continent Islands, happily enjoying the view.
Heartland USA in Sgt. Pepper's Lonely Hearts Club Band pretty much fits the bill. But once Mean Mr. Mustard steals the magical instruments, installs evil 24 hour Video Arcades, and puts the ultimate sign of evil...a giant hamburger....atop the town square bandstand, everything goes to heck!
Pepperland in Yellow Submarine (before the Blue Meanies attack) is a more adult version.
Literature
The Land of Oz under Princess Ozma, despite periodic threats from outside and certain parts of Oz of being way out there, generally follows this trope.
Only when ruled by Ozma, though. If someone else takes the throne, generally you get a Crapsaccharine World (i.e. Jinjur's revolt, the witches running wild).
The Bible has the Garden of Eden. Plenty of food, all animals are vegetarians (yes, even lions, female mosquitoes, and fleas), no disease, no guilt, and you never die. Also, everyone is perfectly formed and naked. After Armageddon, the new Earth will be identical. Many Christian offshoots emphasizing Armageddon have a tailor-made second Earth; fundamentalist sects ignore the nudity, while indigenous versions, such as the Ghost Dance, tend to ignore the vegetarianism. Of course, the nudity pretty much ensures the FCC will never have a children's story in Eden.
In Mary Kirchoff's Kendermore (from the Dragonlance series), Tasslehoff Burrfoot and his human companion wander into a portal that takes them to Gelfigburg, a realm created by a kender with a magical amulet who happened to be extremely hungry. The whole city is made out of candy and all its kender residents are obese but happy and contented.
Speaking of A Series of Unfortunate Events the series parodies these quite beautifully with a fictitious novel (or movie if you feel inclined to watch a DREADFUL movie like A Series Unfortunate Events.) called The Littlest Elf. The reader is told constantly that it would be a better idea to read The Littlest Elf seeing as the book you are reading is unhappy and therefore should not be read by anyone. The Littlest Elf is a running gag that even comes up in Lemony Snicket's "Biography."
For all its attempts at Darker and Edgier, The Looking Glass Wars really turned Wonderland into one of these. Its capital city is known as "Wondertropolis", there are foods with names like "Tarty Tarts", and even worms are known as "gwormmies". Of course, then Redd takes over and the place becomes a Crapsack World until Alyss returns to dethrone her.
Live-Action TV
Barney & Friends: Wherever the hell Barney the Purple Dinosaur lives.
Pushing Daisies: An example that is not a kid's show. To balance it out, we get Deadpan Snarkers Lily and Emerson, and a whole lot of murder. Adorable murder.
The Puppet Land that Pee-Wee's Playhouse was set in.
Captain Kangaroo's Treasure House.
Music
The work of Adam and the Couch Potatoes is very much this, in a good way. The music is full of life and happiness, and very uplifting.
The video for the Katy Perry song California Gurls is set in one of these places. With a twist.
Aqua's 'Lollipop' has music and lyrics which define this trope. It also helps its genre is a super sugary brand of eurodance.
The 1933 song "Good Ship Lollipop", later sung by Shirley Temple.
Newspaper Comics
While theoretically set in our world, Rose is Rose is constantly on the brink of this. The word "die" has never been used and will never be used, nobody ever suffers even minor injuries, no one is ever more than mildly embarrassed unless they're overreacting, no one has ever gotten a bad grade on their report card, and swatting a fly would be a major Out-of-Character Moment for anyone in the cast. It's slightly disturbing to realize that Sesame Street has gotten darker at times than this ever will.
In the Dungeons and Dragons setting Planescape, the Outer Plane of Elysium isn't quite this goody-goody, but it's still filled with magical Good-aligned humanimals, brims with bounteous natural beauty, and has an inconvenient habit of turning anyone who stays for more than a week or two into a blissed-out hippie zombie who has completely forgotten why he came there and has no desire ever to leave.
This trait is only shared by the planes evil counterpart, the Gray Wastes of Hades, and endless plain of gray dusts. Except that it doesn't make you happy at all. The only reason people don't just lay down and die is that it's futile as most of them are already dead to begin with.
Babes in Toyland in the play and most film adaptations. Operating word being "most"; the late 1980s made-for-TV version featuring a pre-teen Drew Barrymore and a young Keanu Reeves had its horror moments.
Video Games
Animal Crossing: In all the worst ways, in Chewbot's Let's Play. Yahtzee did one too; this one used the "indoctrination" aspect of the trope.
MySims and the sequel MySims Kingdoms, wherein your job is to make it even better.
Super Mario Galaxy has the Sweet Sweet Galaxy. It only has one star and happy (and familiar) music plays through the level. And, the star is found on a giant cake.
Ironically, the actual gameplay of this level is one of the most difficult of the early game.
In fact, the entire Mario series could probably qualify. The mushroom kingdom may be themed after fungi instead of sweets, but it's also an idyllic land where toadstool people romp happily and the only real problem the kingdom ever seems to have is Bowser's penchant for kidnapping the Princess. A problem Mario consistently resolves in short order.
Played for laughs with Toonstruck's Cutopia, ruled by a giant smiley face.
Vigilante 8 on the N64 had a bonus map called Super Dreamland 64.
Touhou: Once you get past the customary greeting, Gensokyo could very well qualify. Nobody ever dies (except that one bat), all the notable locals are Moe Moe girls, and whenever something goes horribly wrong, inevitably the Miko and the Cute Witch save the day and befriend whatever was causing the problem.
Most Harvest Moon games are this sort of world. A Wonderful Life is a little darker, but only in the fact that it deals more with actual real life issues than the other ones do.
World of Illusion for the Genesis has Mickey Mouse and Donald Duck traveling through a giant kitchen. Two of the rooms are literally the inside of a Sugar Bowl and a whole candy and chocolate Themed world.
Kit'n'Kay Boodle is a VERY adult variant. (Warning: Will make you very sick of the word "Yiff.")
The (former) page quote from Order of the Stick is some kind of inversion of this trope: the place Belkar is calling "Happy Fun Sunshine Land" is actually a city where it is not odd to walk down the street carrying a corpse with your dagger still in it. He calls it that because he's feverish and delusional from the Mark of Justice curse, and has no idea what's actually going on. The magical fairy part is the only accurate part.
"Be very quiet, Mr. Scruffy! If we make any noise, the magical Cart Fairy might not take us on the enchanted trip to Happy Fun Sunshine Land!"
During the "Dimension of Pain" Saturday story arc, the Dimension of Pain was taken over by a sneaky angel who managed to briefly turn the Dimension of Pain into the Dimension of Fun. The demonic hordes became Care Bear parodies of themselves and the Demon King was turning into Mister Rogers. Fortunately, Lord Horribus returned from his exile and managed to make the angel Fall and become demonic, allowing the Dimension of Pain to be restored to its original evil. Yay!
The "Dimension of Lame" is naturally like this, even if it looks more like our world.
Torg: "Why the BLEEP
Yes, the dimension has naturally occurring censor bleeps.
does it smell like flowers down here?"
Alternate Zoë: "It's a sewer, silly!"
Sugar Bits has Confectionaria, which is exactly what it sounds like.
Web Original
Uni Creatures is set in one, right down to their being no carnivores (that big scary lion on fire? He eats fruit.) to avoid the violence and pain of creatures hunting each other.
The Gummi Bears may be an exception to this— or at least not as happy go lucky as the other Disney shows. True, they live in a pretty happy Medieval world standard to the trope, but they are the last remnants of their once great race/civilization on Earth (well, the European part of it anyway) with a certain amount of sadness and Zeerust thrown in as well.
The Magic Roundabout would almost certainly count if it weren't for both Dougal and the Blue Cat and the recent movie
My Little Pony has a reputation for this. Not entirely undeserved, especially in the cartoons for the G3/G3.5 toyline, but the pilot specials, The Movie, and the original My Little Pony and Friends show had the ponies frequently dealing with supernatural threats to their peaceful lives, ranging from rampaging monsters to wicked witches to Evil Overlords.
My Little Pony Friendship Is Magic takes place in a world where ponies can move the clouds around to make it rain or shine, and plants and animals need to be told to grow or hibernate. Thus, changing seasons is a large community project. The inhabitants are so accustomed to this way of life that the Everfree Forest - an untamed wilderness where animals take care of themselves, plants grow on their own, and weather occurs independently of pony intervention - is considered spooky and unnatural. And again, there are monsters aplenty.
The Smurfs. Gargamel has only succeeded in making one permanent change to the Smurf Village - introducing a female smurf.
The Powerpuff Girls: Him tricks Bubbles with one of these in "All Chalked Up." Clever — who would suspect a place like this of secretly being the creation of an evil, manipulative demon?
In an episode of Project G.e.e.K.e.R.: Geeker, Noah, and Lady MacBeth are chased into a run-down amusement park. They encounter interactive holograms that adapt to the visitor's "play setting" - with adorably goofy, brightly-colored cartoon bunnies being the default mode. (That is, until Lady MacBeth's short temper triggers their "battle mode".)
In an early Simpsons episode, Homer sarcastically evokes this trope in a bitter moment ("Oh, look at me! I'm making people happy! I'm the Magical Man from Happy-Land, in a gumdrop house on Lollipop Lane!").
In another episode, he misinterprets Germany's status as "the land of chocolate" in a memorable dream sequence. Homer imagines Germany as a land of fudge rivers and candy cane trees, where chocolate bunnies romp about just waiting for someone to come and eat them. By the time the man he's speaking to snaps him out of it, 10 minutes have passed.
The Happy Little Elves, a Show Within a Show seen in some early episodes, seemed to be an example of this trope.
Wonder Showzen: Parodied in an animated segment "The Boogie Noogie Bunch".
ThunderCats: The Ro-Bear Berbils seems to be space-colonists from the Sugar Bowl. And true to their nature, they've set up a little piece of Sugar Bowl right in the middle of the mutant-infested swampland of Third Earth. A place filled with houses shaped like giant, pink mushrooms, where candy-canes grow in orchards. They also talk like Smurfs, and all have names starting with a B. Isn't that right, Ro-Bear Bill? Berbil-fruit, anyone?
In the Thundercats UK comic we saw that Sugar Bowl was a deliberate choice. They used to be cyborg-Bears rather than cyborg-Teddy-Bears but they are trying to be Space Amish while still having the Superweapon Surprise technology in their underground facilities to rebuild themselves in their spacefaring warlike image (the Thundercat they showed the hologram of what they used to look like was impressed enough to instantly agree to help them restore their facade of cute harmlessness).
In the Darker and EdgierThunderCats: Dogs of War, they are wiped out by the Lizard Men after welcoming the invaders with flowers. This can probably be seen as trying too hard.
In the Teen Titans episode "Nevermore", between all the nightmarish landscapes that Beast Boy and Cyborg run into is one of these. Complete with floating strawberries. Beast Boy quips, "This must be where air freshener comes from."