Silver watch is a very good and worthy gift,but it's also an expensive gift. A framed photograph of the school will always remind him a good memories. A set of leather , I do not think that it's a good idea to give a such kind of a present, we need to present him something special which will leave memories about us)Bound books of literature classic is the most worthy gift,it is very useful and interesting,as books have always been a source of knowledge !I think that camera is the usual gift,and teacher can buy it himself,I'm sure that books are better,as they can't break as camera.