I have had far more than my share of naysayers, and have been trying to come up with a non-confrontational way of saying, "I don't want to hear any negative views of our plans" without sounding pious or snobbish. It's tough, though...people really, really want to be "right" and will push and push (no pun intended) that their way is the "right" way. We are practicing our HypnoBirthing breathing and "homework" almost every night, and we are surrounding ourselves with positive influence and encouragement.
I'd highly recommend (but I won't push) that anyone who is considering having a baby look into midwifery, whether they are planning an unmedicated birth or not (most midwives will attend births in both Birthing Centers and in the standard Labor and Delivery ward of many hospitals.) There are very few complications in pregnancy that a midwife is not qualified to handle (we've tested THAT theory numerous times this summer), and they really treat the pregnancy as a family event.