Peercoin.
There are no "currently hot sha256 coins", this statement includes Bitcoin itself.
The point regarding pure POW sha256 coins is blockchain security against fork attacks. Peercoin is safe since it is additionally secured by staking. Small coins cannot rely on any algorithms where monster supplies based on ASIC technology do exist.
I know peercoin has been around for a while, so that's a plus, I think. I'll look into this one. Also, I think I understand your point about easy forking attacks against a new coin because of asic resources.
On, unobtainium, I'll look into this one as well. I have to admit, the name sounds like a joke from sci-fi, but maybe there's more to it than that.