Firstly there are different types of headsets..
Integrated Headsets: For frames with integrated head tube (bearing cups are built into frame)
Press Fit Headsets: For frames without integrated head tube, therefore the headset includes the bearing cups.
Be aware that there are 2 different types of integrated head tube...
Campy Spec: For integrated headset with 45 degree micro angular contact bearings
Cane Creek Spec: For integrated headset with 36 degree micro angular contact bearings
As far as I am aware the Giant Reign runs a Campy Spec integrated head tube so you will be looking for a integrated headset to suit.
Can a fellow reign owner confirm whether the headtube is campy or cane creek spec ?
As of yet I don't think Chris King make an integrated headset so that option is probably off the table.
I suggest a higher end FSA headset, FSA has been in the business for a while and they make good quality headsets. One of the reasons people like to spend massive amounts on headsets is for the bling factor but with an integrated headset there is no real need for bling because well there isn't much of the headset to be seen. So a good quality headset is a better choice over a blingy or fancy coloured one.
Have a chat with your local bike shop and see what they can do for you..
