The right number of pipes is the right number of pipes. For me, that used to be 40-something, but I figured out what I like and I've only got a couple out on my shelf now.
The rest are having a nice nap in the closet until I want a change of pace, then I'll just rotate out a new set. Keeps things tidy, I never get bored because of the variety, and my wallet is once again on speaking terms with me.