I would keep ALL the coins that i mine, and buy stuff i need.
Thats how you support the community of BTC in 2 way's : you mine and buy with BTC
Profits will decline eventually so be wise on how you spend it.
There will be another crash if you believe the reason why most people intend to mine in the first place
So they can retire from work (hahahaha) al those calculators (except for the gen.block)
Promise amounts of money most people won't ever get close to.
This is how i would do it, wait for the NEXT big crash, wait untill it gets back up on a decent USD/BTC price again
And maybe then sell some, but i have high hopes for the long run (10 y or so) so i would still keep some.
(Btw all the investments i made, i did that with spare money i wouldnt care if i would lose, so im already happy with any income on BTC)
I sold my only house and auctioned off my children with a buyback clause at 10% premium to buy my miners.
KnC Better deliver on time (Do it for the children)
The preorder thing is a big gamble. But how could you have chance for big profit without willing to risk a lot - seems fair