One year I was the "room parent" for one of my children's classes. I contacted all the parents and asked for them to donate (if they were interested) to a gift certificate for this teacher. One mom told me she was so excited becuase she wanted to get a gift but couldn't think of anything.
This is where I'll probably become really unpopular. As a person from the "other side of the pupil" for a while (that is being the teacher), I think all gifts are wonderful and the love that goes in to something you have made is extremely special. Most teachers have a closet full of totebags that never see the light of day. People forget that teachers spend hundreds of dollars of their own money every year buying things for their classroom. The most useful gift I ever received was the gift certificate.
Now this and $0.02 will probably get be a train ticket to somewhere far away.