Icing on the cake would be the John Williams theme as the opening credits. It's as synonymous as the James Bond theme
I think that's an overstatement. The Bond theme debuted in the first Bond feature film and has been used in every one except
Never Say Never Again and the '50s TV and '60s spoof versions of
Casino Royale. But Williams's Superman theme was itself an homage to the two previous major Superman themes, Sammy Timberg's theme from the '40s cartoons and radio series and Leon Klatzkin's theme from the '50s TV series. The Williams theme has been used in only five movies, the 1988 Ruby-Spears animated series (alongside an original Ron Jones theme), and on a few occasions in
Smallville, but there have been multiple Superman productions that have had their own distinct themes, including the '60s Filmation cartoons (theme by John Marion Gart), the '80s
Superboy (Kevin Kiner),
Lois & Clark (Jay Gruska),
Superman: The Animated Series (Shirley Walker),
Superman: Doomsday (Robert J. Kral), the later seasons of
Smallville (Louis Febre), and the current movies (Hans Zimmer). So there's a far greater variety of Superman themes than Bond themes. Sure, Williams's Superman theme is one of his best compositions (it's one of my two favorite Williams movie themes alongside the Indiana Jones theme), but a lot of the others are really good too, and Superman music would be far poorer if all anyone did was just quote Williams over and over.
I feel that the Berlanti shows' composer Blake Neely has done a terrific job with the various hero themes in these shows, and I think he absolutely deserves the opportunity to make his own contribution to a tradition of Superman music that extends far beyond any one composer, even Williams.