We have two really awesome bus drivers. Each year I make them homemade goodies like cookies, banana muffins, etc. and then I include a little gift. One year I gave them each a coffee mug that said #1 Bus Driver that I ordered from Oriental Trading. One year the gift was a nice pair of gloves as they have to go out early on snowy mornings and at times put chains on the bus! They look forward to the homemade goodies and the kids tell me that they usually dig into them as soon as they get them LOL.
Teachers are a little harder. Homemade goodies are great here, but it's a small community and everyone knows everyone. In a larger school I can see where teachers might be leary of eating homemade goodies. I've done really pretty windchimes, teacher Christmas ornaments (these have been a particular favorite of the teachers that my kids had), an Italian Charm bracelet with charms of things the teachers loved, gift certificates, etc. Mine are old enough now that they each have several teachers so we won't do gifts this year for them.