Blog@Newsarama’s Agent of S.T.Y.L.E. feature has been running a three-part series by Alan Kistler on the Flashes’ costumes.
*Update: The Blog@Newsarama pieces are gone; Kistler has moved the column to The Mary Sue, and has run an updated version of part 1 (link updated above).
On a related note, a few years back I put together a comparison of Wally West’s costumes, or at least those that contributed elements to his current outfit.
Nice picture, which predates and kinda predicts the current two Flashes (Barry’s back + Wally in a similar styled costume)!