As a teacher, my fav gifts have often been books a child or parent has picked for me. I love reading and often would wonder why a book "found me" at a particular time. What was the hidden message? I feel a very special connection to students who have given me books - especially with notes or inscriptions.
As for gift cards, yes of course I like those too. But make sure they are good gift cards for the recipient. I get about $200 in Starbucks cards every year - and I don't drink coffee. I don't mean to sound ungrateful - but man O man would I love to have that 200 bucks towards something I really like.
This year, I received another gift I really liked! I got a Whole Foods Feed Bag. This is a spendy reusable grocery bag but the money funds school lunches in impoverished countries.
Lastly, about the homemade goodies. While they are appreciated, I usually have a family vacation planned close to the time they were given. Sometimes I have time to drive to the local shelter and donate the dozens of cookies and candies and breads before I go to the airport. But sometimes, sadly, they just go bad and are wasted.
In a nutshell: do a little research. Trust me, your teacher will be blown away by the "perfect" gift. The one that says you care as much about her/him as she/he did about your child.