First things first,
THIS IS ONLY BASED ON THE COSTUMES. For this ranking, the scenes the characters were in
DO NOT MATTER. This is only for the costumes, and nothing else. It is a mixture of how awesome/close to the comics the costume looks and how realistic it is. That being said, I repeat
IT IS ONLY THE COSTUMES, NOTHING ELSE. Now onto my list.
1) Pietro Maximoff/Quicksilver (Age of Ultron Version)
I rank the Quicksilver from Age of Ultron as first because the outfit from the set pics so far (see left photo) looks pretty close to the comics. It has the blue and the white lightning. In addition, I do not believe that it is the final costume, I believe by the end of Age of Ultron, or Avengers 3/whatever-the-next-film-with-Pietro-is will have a final costume, I think that the final costume we see Quicksilver in will be much closer to his comic book counterpart, probably similar to the concept art (see right). Also, the one from the set pics is very similar to those that professional athletes would wear, it is skintight and allows for fast movement. From what we know, Quicksilver and Scarlet Witch are with HYDRA, not allowing them for proper costumes. I give him about a 8/10 overall.
2) Barry Allen/The Flash (The Flash)
I rank this costume number two because it truly looks like it jumped right off the pages of the comics, it looks like the costume from the comics. My only beef with this costume is that I'm not too sure it would work in real-life, or else I would have rated it highter. It looks really awesome, almost exactly like the comicbook costume, from the symbol on his chest to the helmet/hood. Same color scheme same everything, just really awesome. I rank this about 7.5/10
3) Peter Maximoff AKA Quicksilver (Days of Future Past)
There is only one thing I can say about the Quicksilver from Days of Future Past, His. Costume. SUCKS. I understand that his pats in the movie takes place in the 70s, but Quicksilver first appeared in 1964, and his costume in his first appearence is still better looking than the one in DOFP. I don't care how good his scene was, this list is purely about the costume, and the costume isn't pretty. The comic Quicksilver (right) is from his first appearence in the comics, and it still looks better. I don't think it would be easy to run in a pleather jacket, and the Walkman and goggles are useless. Quicksilver can run without anything bothering his eyes because of his powers and he runs too fast to get much use from a Walkman unless he was running for a while. I give this a 2/10, it looks plain old stupid.
There is my list. If anyone can prove that The Flash's costume would work in real life, I will be willing to put him as number one.