I can't remember when my adoration for Perhaps, perhaps, perhaps (the song) started but whenever I listen to it I fall more and more in love with it. The importance of this song in popular culture is demonstrated by the many movies it is featured in - In the Mood for Love (with the original Spanish version, written by Osvaldo Farrés, performed by Nat King Cole with a very English accent), Bad Education by Almodóvar (lip-synched by Gael Garcia Bernal), Brokeback Mountain (also in Spanish), Running with Scissors, Quand J'Étais Chanteur (performed in French), etc.
The most famous versions are the original Spanish one, the Cake cover (from 1997) and the Doris Day version.
Gael Garcia Bernal "performing" Quizás, Quizás, Quizás in Bad Education
Below are four videos, the first one performed by Cake, then the one with Doris Day. The third is Nat King Cole's version and last, but definitely not least, the French version.