Use PEX.

Two years ago we discovered that our copper piping had sprung a pinhole leak. By the time we found it, water had already seeped through the walls and ceilings. It was a costly mess that required replacing walls, ceilings and flooring. We learned waaaaay too late that it was the "deadly" combination of water with low pH running through copper pipes for 35+ years that was the likely culprit. (We have well water). After getting several local pros to assess the situation and make recommendations, we ended up replacing ALL of the copper piping in the house with CPVC. We considered PEX as well, and would have been satisfied with that, but the contractor we wanted to work with was more in favor of CPVC. I also spent a fair amount of time reading through the plumbing forums on www.TerryLove.com. That was VERY helpful. Good luck!