I remember very fondly the 1980 Eurovision Song Contest, which had only few (if any) bad songs and some of the good songs were the best in the whole Eurovision history.
The Spanish entry that year differed from the norm in many ways. Melodically the song was very dynamic, each verse was different with interesting tempo changes. The icing is gorgeous orchestral arrangement (which can be heard in all its glory in the recorded version of the song, here synched to the preview video).
This combined with stylish and flawless performance by a popular Spanish trio Trigo Limpio made this song wonderful example of the early 1980's Eurosong at its best. The 13th position in the final results (among 19 songs) feels a bit too low, but as I said, the competition in 1980 was tough.
My points 5/5.