I love getting student made ornaments (include the child's name and year). It is so fun to look back each year and remember the little lives you been a part of.
I seriously can NEVER have enough office supplies, so I love getting gift cards for Staples or Walmart.
It is also well known that teachers can NEVER have enough books. A gift card to Amazon is awesome. I like to write inside of the book, "This book was purchased by_____" and I put the name of the student who made it possible.
Best of all? Cards and notes written by my students...the BEST!