Depends on the character and the costume.
In nearly every TV appearance of Wolverine, he's wearing the yellow-and-blue costume with the mask, as that's the look most frequently associated with Wolvie. Though I personally prefer the black costume with no mask.
Similarly, I prefer the all-black movie costume on Batman to the black-on-gray suit he typically wears in his animated appearances.
I always seem to prefer Superman's alternate costumes (his Justice Lords suit from "A Better World", his dictator suit from "Brave New Metropolis", his future suit from "The Call", his clone Superman X's costume from
Legion of Superheroes season 2) to his original costume. Guess I'm just not a fan of manties (man-panties).
Regarding
Teen Titans, I preferred Starfire's comic book look, but they'd have never gotten that look past the PTA.
I was a fan of
Fantastic Four: World's Greatest Heroes, but I wasn't too thrilled with the mostly-white-with-blue-trim costumes with the '4' logo in an orange circle. They made the team look like walking Rocket Pops. And don't get me started on Thing's sweatpants with a white triangle on the crotch that makes him look like he's wearing low riders and a '4' spray-painted on his bare chest. If Reed Richards can design a costume for himself that can stretch and contort to every shape he can mold himself into, a suit for Susie that can turn invisible along with her and a suit for Johnny that doesn't burn up when he flames on, you'd think crafting a shirt and shoes for Ben wouldn't be that big a chore for the smartest man on Earth. I would've gone for the dark blue costumes from the recent
Fantastic Four live-action movies, but that's just me.