bodenbabe I have big norks and it isn't so much the shape of the neckline as the height of the neckline that is problematic. I avoid anything that has a roll neck or high neck (slash necks, high scoops etc).
You should have some cleavage on display otherwise you look bulky (especially when you are also short) but just be aware that many tops designed to show cleavage can look ridiculously OTT on those large of nork.