The bank employees are really great as well, they even bring the artwork back to the school, and pick up the next set of artwork. Each elementary school in the area is invited to participate
The parents also really like being able to take their students to the bank to look at their artwork!!! We get lots of compliments for community members as well. It is a great program all around.
This Ning website has a discussion forum on rewards for students in art. I found it interesting and posted the information from this blog as an answer to the behavior question.