Source: Action Comics #236 (1958) Type: The real deal (since retconned)
The story that dares ask "If Superman ever found it necessary to discard his famous super suit, what new costume would he adopt?" It's the Man of Steel's first major rebranding and it's a FASHION NIGHTMARE! It all starts when Superman lends his indestructible super suit to Professor Carlton so he can test his dangerous atomic robot called Metallo (not THE Metallo, he's a year out, but still the third entity in Superman's life to bear that name; it's pretty popular). Metallo III is a bust.
In the resulting chaos, Carlton - actually Lex Luthor in a Mission Impossible mask - switches out the super suit with an imitation. Oh, dastardly. Over the course of the next few hours, the suit gets ripped to shreds by the threats Superman inevitably faces! He returns to the Prof who confirms the explosion must have affected the super suit on an atomic level, but no worries, the scientific community is on it, they'll make a new suit for the rigors of superhero action. In the meantime, Superman goes WAY too far trying to rebrand.
I guess the armor, but did he have to change his entire shtick to a knightly theme? Metropolis is understandably confused. I don't know what the merchant navy thinks. A week later, Prof Carlton presents Superman's new uniform. Warning: May cause pinkeye.
They COULDN'T have made it red and blue? Or included the big "S"? No. These guys are scientists, not fashion designers! They like to label things! And tinker! That's why they've included more powers into the uniform. A built-in radio so Superman can hear police calls, winged boots for stealth flight so he can stop making that dreadful WOOOSH (a noise that apparently creates avalanches), gloves so he can stop worrying about Lois Lane finding his fingerprints pressed into hard steel (I know it sounds like I'm joking, but these are arguments right out of the comic!), and it glows in the dark too (great for leading ships out of fog). But wait, there's more! How about an Anti-Kryptonite Belt?
That's right. It protects Superman against that fake kryptonite Luthor just handed him. So over the course of the next few days, the new uniform seems to be a great functional success, though as a brand, it leaves a lot to be desired. What Superman doesn't know is that it's all part of Luthor's plan to make the Man of Steel go out of fashion. That's right. He's about to re-introduce Classic Coke!
Luthor, in the super suit, shows up to discredit this obvious poser in the yellow and purple, and lets cops shoot him for fun, seeing as the suit lends him some invulnerability. Can New Coke Superman prove he's the real deal? No, because he's suddenly being poisoned by the kryptonite hidden in his Anti-K Belt!
Superman lay dying when he suddenly flies into action and gets Luthor to blurt out the details of his scheme.
Silver Age characters are so used to explaining "what's really going on" that they just can't help themselves. So I'm looking at this page and I think I KNOW what's going on. It's ironic, see, because Luthor gave him those flight boots, and thus the means Superman uses to defeat him. Nope. That would be too easy and make too much sense. Here's the REAL explanation:
That's right. Despite losing his powers to Green K poisoning, he managed to tap out some super Morse code picked up by Jimmy's signal watch, who then translated an urgent but convoluted message and sprang into action, rigging a powerful magnet to the Flying Newsroom, finding Superman, dragging him up and dropping him on Lex. All before the charity event was over.