I want to email a copy of my thesis to the thesis committee, should I thank them that they are serving on my thesis/dissertation committee? and how should I thank them? (it is before my defense))
You should thank them by acknowledging them at the end of your defense (i.e. the acknowledgment slide of your PowerPoint presentation). Keep it professional though. Once your defense is over and you are cleared for graduation, then you can shake their hands and get a beer.