I can't see why it would hurt. Although, thus far, anytime I have had someone write anything for me for anything I have just thanked them in person as it is usually someone I either worked with or know. I suppose it is just dependent on who the person is and in what capacity you know them.
I wrote a thank you letter and included a small giftcard for something they liked (ie one professor was a coffee-a-holic for dunkin donuts so gift card for that).
A simple email showing your appreciation should suffice. You can maybe go above and beyond to an individual(s) you're personally acquainted with quite well.