Hi George You are right to be concerned about this water pipe. The key concern to you is the chlorine level in your water. I can't recall specifically what the parts per million threshold is, but I think any water with over 7 ppm chlorine is a candidate for poly butylene pipe cement to fail...meaning the pipes joints will eventully burst. I'm not 100% sure on this and am doing if from memory only...so you might want to check.
As to replacing the existing pipe....copper is really your best bet. I know, sweating the joints in a crawl space in between floor joists is not one of life's more pleasant jobs....and I dislike it too. But in the long run, copper will be the most dependable, least likely to fail and virtually maintenace free (provided it doesn't freeze :-)
However, if you absolutley must reinstall plastic, I use CPVC, which is approved in most areas for hot and cold water. It glues up with its own special (yellow) adhesive and goes together just like PVC pipe...so its quite easy. They make a copper-to-cpvc union that you sweat onto the end of the copper run and then glue your CPVC to the other end.