The Flamingos first got together in a Chicago synagogue. They just churned out hit after hit after hit in the early '50s. Versions of the band still perform and in 1998 they successfully sued Pepsi for using "I Only Have Eyes For You" without getting permission. They raked in a quarter million for that!
Something tells me that not too many LNMC fans were alive when Dick Powell and Ruby Keeler first did "I Only Have Eyes for You" in the film Dames (1934). The Flamingos version came out in 1959 and is totally the classic (despite also having been covered by Sinatra, Peggy Lee, Art Garfunkel and The Letterman). Afterall, when it showed up in Buffy, this was the version.