During the Silver Age, there was a strong attempt to avert this by making it's villains as uncool and incompetent as possible since one of the rules of the Comics Code was that "crime shall not be portrayed as glamorous." YMMV on how succesful they were.
It doesn't matter whether he's a giggling, goofy clown prince of crime (e.g. the 60's Batman (1966) television series), a mass-murdering, manipulative, and psychopathic Monster Clown (e.g. The Dark Knight), or a seemingly impossible mixture of the two (e.g. Batman: The Animated Series), he will inevitably overshadow every other character, have all the best lines, and, while Batman will always have the best toys (he's the goddamn Batman, after all), the Joker will find the most creative and spectacular ways to use the tools at his disposal. No matter what he does or who he does it to, he will make you laugh, because of the simple fact that he's just that good.
Discussed in an issue of Batman: Black and White, a short-story anthology. In this story, "A Black and White World", Batman and the Joker are actors playing their comic book roles as if they were roles in a movie. The Joker brings up the fact that Batman always gets to make a big, dramatic, splash-panel entrances, complaining that he never gets to look that good. Batman then points out that the Joker always gets the best lines, while he just has generic crime-fighting hero lines.
Batman in general is a magnet for this. When your main character is a traumatized billionaire dressed as a bat and you have villains drawing your attention far away from that, it really says something.
Le Tueur: I have a confession to make: I only like the Batman because he has the best villains!
In the Marvel Universe, Doctor Doom practically owns this trope. He's a science genius (and a wizard) who wears a cloak and a suit of armor, rules his own country, and lives in a castle. And refers to himself in the third person! DOOM insists on it!
He has willpower strong enough to effortlessly resist commands from an extremely powerful mind controller (who was at that same time controlling everyone else on Earth), has gone toe to toe with Celestials, became a physical god and almost single-handedly saved the multiverse, and many other things, even more if you count his appearances in elseworlds. His life is a series of escalating moments of awesome, and is so confident and competent that many fans end up agreeing that the Fantastic Four should just go ahead and let him conquer the world, since he probably would succeed in making it the utopia he claims it could be. In fact, in at least one elseworld, that's exactly what happens.
Magneto, while officially fairly heroic since House of M and having gone through the Heel–Face Revolving Door for 20 years or so before that, owns this trope. He's immensely powerful, capable of trashing entire teams of Avengers and X-Men all by himself (his repowering during New Avengers induced a Mass "Oh, Crap!" in the titular team), with shields capable of (just about) holding off blasts from the Phoenix and Galactus. He's also ridiculously intelligent, with self-made space stations considered on par with Reed Richards' work, highly cultured, a Silver Fox from the late 70s onwards, a hero in several alternate universes (most prominently, the Age of Apocalypse, where he led the X-Men), and as a Holocaust survivor, he has the mother of all Dark And Troubled Pasts - as well as the very sympathetic motivation of "never again". Being played by Ian McKellen and Michael Fassbender doesn't hurt, either.
Archangel from the X-Men. He's the Superpowered Evil Side of Angel, whose power is... flight and decent (not great) healing. Archangel has metal retractable wings which are dipped in poison and can be launched. Said wings are also razor sharp. Also, Archangel just looks cool. Needless to say, a lot of fans prefer Archangel.
Monsieur Choc, the main villain in the Tif et Tondu Belgian comic book series. He is considered so cool that he is the reason the series became popular in the first place, and the recent re-releases deliberately put him as the focus on the covers of the stories chosen.
Played with in Sin City. The pure evil characters are usually pretty ugly and often cowardly, or just plain creepy. Some of the good guys, however, are at the extreme end of anti-herodom. The most popular tend to be Marv, Dwight, and Miho, who would normally be considered bad guys in any other work. They are also damn cool.
One arc in The Sandman features a convention of Serial Killers who think of themselves as this (they pick impressive-sounding names for themselves and think of themselves as Übermensch), but as the reader sees more of them their combination of petty delusions of grandeur, personal insecurities, copying of their predecessors and occasional stark-raving-madness becomes more obvious. This is ultimately confirmed when the eponymous Morpheus gives them all a blistering "The Reason You Suck" Speech, tells them that "Until now, you have all sustained fantasies in which you are the maltreated heroes of your own stories. Comforting daydreams in which, ultimately, you are shown to be in the right" and then uses his power as lord of dreams (and thus fantasies as well,) to strip them of their self-deception so that "you shall know, at all times, and forever, exactly what you are. And you shall know just how LITTLE that means."
Darkseid. He's a badass that can go head to head with Superman, and on occasions has beaten him. But he's also a Chessmaster that rules over an entire planet and can come up with schemes that leave the universe trembling before he even bothers to get off his throne.
Loki: Agent of Asgard: Old!Loki, evil dick though he may be, is definitely considered cool. The fact that in his first full outing he successfully manipulated history itself and got away with it might be a factor.
Spawn: Some Spawn's recurring enemies have this like Violator,Disruptor,Sinn,Malebolgia,Freak,Curse,and many more.
Transformers: More than Meets the Eye: While they are a group of truly evil monsters who given half the chance would (and could) murder the entire cast, the Decepticon Justice Division count. And their leader Tarn in particular. It helps that most of them, Tarn in particular, just look badass.
Black Moon Chronicles: Make no mistakes about it, Haazheel Thorn is pure evil, but there's something to be said for an archmage who had enough will of mind to build an entire religion around himself, effortlessly slaps around giant demons, has a succubi harem, can resurrect people from the dead, transforms into either a hulking behemoth or a four-armed Kaiju monster, and lives in a fantasy moonbase.
Torquemada is in the running for most evil villain in all fiction, but he's not a coward by any stretch of the imagination, tending to fight his much stronger foes like Nemesis hand to hand. When Nemesis ripped out his heart, Torquemada's undead body killed the monster that ate it and restored his soul through sheer willpower. Plus, his menacing fashion sense.
Nemesis himself is a powerful demonic Magic Knight with a bitchin' spaceship telepathically linked to him. While far less evil than Torquemada, he's no saint himself, and while he regularly goes up against the Terran Empire, Nemesis is essentially doing so because he's a Troll.
Vandal Savage. An immortal supervillain who practically invented evil, has fought virtually every great superhero in DC's canon and lived to tell the tale, and makes every move with style. He is also an exceptional Magnificent Bastard, willing to commit every form of crime (and probably already has throughout history), is on par with sadism with Victor Zsasz and the Joker, or all people, has an intellect matching that of Luthor and Ra's al Ghul, and manages to look menacing or otherwise badass in any outfit he wears. Who else could possibly make an 18th century Victorian outfit look cool in modern times?
