As much as I would love to go off on a list building spree, I think it might be a waste of time doing it for Nova Open. Primarily because the new Black Templars codex is likely to be released prior to the event in August and I will have to create totally new lists anyway. I'll stick to building lists for the other two GTs (well, only one at the moment) I'm attending this Spring/Early Summer, since its unlikely a new codex will be out by then.
Which would be my preference, as I decided that my Black Templars will be my permanent Grand Tournament army. I just felt like I was betraying my over ten years of playing the BT if I would have brought the Dark Eldar. So I'll keep my DE for the more local tournament level stuff. They are more for a change of pace anyway. ;)