Demonology for me.
In terms of the specs as is, if your not pushing server firsts or heroic progression ,you can pretty much play any spec you want. The issue I see however is why would you bother playing Affliction or Demo, which are more complex rotations and styles, over Destro which is easy and forgiving, yet provides better DPS.
I don't personally like Destro because I find it a carbon copy of a Mage, I'd prefer to be playing Affliction or ideally, Demonology.