For Sagittarius any holiday has some sense, that's why if you gift to him a present, it shouldn't be standard or impersonal thing. Sagittarius should see that the present was bought especially for him/her… Present him something to the point, with meaning, stressing that you believe in his exceptional talent and that a day, when the whole world would know about your beloved, is just around the corner. Emphasize how you value his advices, erudition, professional skills…
Sagittarius is a sign of Philosophy and Religion. People, born under this sign are very often polyglots and scientists. So, if you want to get thanks from your beloved, present something intellectual to him. For instance, a book by Castaneda or subscription to a favorite magazine.
Sagittariuses are impulsive people, you can surprise them by presenting an air ticket for some journey… It would be the best present for Sagittarius! If you don't have opportunity to arrange such a present, gift to your beloved