I have a master shutoff (ball valves) for the entire system and it certainly is useful. I also have temperature regulated output as well as a "standard" faucet. The temp regulated water goes though a filter, then there are 2 outlets, each with it's own shutoff.
I would suggest the stainless steel braid hoses (they should be on your washing machine too).
There are drain fitting that eliminate the need for a separate vent pipe. Not sure how well they work but they would greatly simplify your plumbing.