Very good reasoning not to sell at the moment; and if that is what we're speaking of, of course there are plenty of domains I wouldn't sell now.
However, let's say for instance a company comes around and becomes a Fortune 500 overnight. They then decided that they wanted a name I owned and offered me 7 / 8 figures because that's their marketing strategy they're going for (brandable, product, ect.). I'm not going to say: "No thanks, I wish to keep this domain for the rest of my life and pass it on from generation to generation." (Unlikely scenario, but who knows, look at FB.com-I'm sure the seller is still kicking himself in the ass for not holding out a year or two even today with seeing how high FB purchased other assets for)
To say you absolutely won't sell a domain is somewhat ridiculous because everyone has a price.
Honest question though: If you wrapped 1-4 up into a packaged deal, would you not sell it for 72-144 multiples or a fixed negotiated price today with an unknown future on them and walk a happy retirement?