I think my favorite hymn is 197 O Savior, Thou Who Wearest a Crown.  I love the message about the Savior's atoning sacrifice and love for man and the beautiful, baroque melody that it is set to.  I attempted a translation of the song into Spanish, because it is not in the Spanish hymnbook, but found it to be much harder than expected.  Here is a rough draft of the first and fourth verses.

O Cristo, tu corona tejida de espinas.
Pesado de dolores, humilde caminas.
Los soldados te burlan, vinagre y hiel te dan.
Y para todos mueres, en la cruz te cuelgan.

A favor nuestro diste tu vida con amor.
A ti, Señor, te damos las gracias y loor.
En los cielos fue hecho el plan de rescate,
Con mucho amor haremos lo que tu mandaste.

Again this is a rough draft.  I want to spend more time on it and work out a really good translation of the hymn. Any suggestions are welcome.