Which universally reviled costumes do you really like? Typically, classic characters who receive updated costumes in a vain attempt to make them more contemporary and cool fall into this category.
Daredevil's Armor Costume (Daredevil 319-325)
It looks badass, and it's obviously functional. I think people associate these costumes with characters at low points in their popularity or creative talent on their respective comics, so they give the costumes the same sideways look.
Superman's "Electric Blue" Costume (1997)
Sacrilege, right? I just personally like the ideas of classic characters evolving and going in whole new directions, iconic status be damned. Not only did the costume change in this case, the powers did too. I though the look of "Electric Blue" Superman was really cool and stylish, and it would have worked on a new character. I also associate this costume with Morrison's JLA, which was badass.
Jean Paul Valley's "Azrael/Batman" Costume (KnightFall/KnightQuest/KnightsEnd, 1993-94)
I enjoyed this story because I knew it wasn't a permanent switch. The new Batman was a completely different character, though, so a new costume had be in place to separate them visually. This is one of the best gothic/creepy character designs and is exactly what I have in my head if I were to picture a more violent and extreme version of Batman. The costume agrees with the character, even if you hate them both.
Those are my picks. Horrible, aren't they?