i think a class pet is a good idea as long as it's being cared for properly and isn't being abused by the children/teacher. we always had hamsters,gerbils, guinnie pigs, parakeets, and snakes in our class rooms. on weekends and holidays we'd draw from a hat to see who got to take the pet home.

i like the idea of having pets in class rooms because if the kids don't have pets at home it teaches them about the responsablility and what it takes to own a pet.