"En este día especial de tu vida" In this special day of your life.
"Special of the day" in Spanish is "especial del día". It is pronounced "eh-spe-see-ALL dell DEE-ah". Please see this site for confirmation of the translation: http://www.answers.com/library/Translations
Soy especial.
Dieta Especial
Características especiales.
You say in spanish, as well, "menú del día".
"Day" in Spanish is día. Note the accent mark above the "i".
I guess you mean "You are special". That would be in Spanish "Eres especial"
"especial de navidad"
Translation: Tú eres especial
especial del dia
Well I am a Hindu and I would say our special day is 'Diwali'.
Enjoy and celebrate your special day