I am thinking (slowly) about doing a sizable addition, including some plumbing. What is the conventional wisdom these days on material: stick with the traditional hard copper or go with something newer like CPVC or Pex. I've sweated many a joint in my day but those latter choices seem much easier to work with.
CPVC and PEX are a lot easier to use, but before you go to any next stage, check what is legal to use in your area. Ask your plumbing inspector and find out what code is for your area. Some places don't allow PEX.