J.B.
I do...if I know the teacher fairly well I'll pick out something more personal but for most, a gift card to Dunkin' Donuts or something enclosed in a card that my child signs works.
I have taught for 7 years and getting gifts isn't the norm but it is very much appreciated. Most of the gifts I've received have been DD cards (which I use even though I don't drink coffee) but I have also received homemade treats, chocolates, flowers, an Avon gift set, and Yankee candles.
Not that any parent wants to hear this, but the biggest gift that parents can give their religious ed teachers is taking their children to church, followed by on-time drop off and pick up and a sincere hello and thank you every now and again. Seeing my students at Mass is way more rewarding than any gift I could get :-)