I have found that the best moisturiser for dry skin is the avoidance of soap. Any soap. Even simple, fragrance-free soap. I use aqueous cream rather than soap as much as possible and have daily stand up washes rather than showers or baths. It has made a huge difference. So much so that I no longer need any other moisturiser.
I've always had dry skin but it has never been less trouble than it is now. I have concluded that excessive stripping away of natural skin oils, which is what soap and related products (body washes, shower gels, etc) do is the main exacerbater of dry skin so if we didn't do that we wouldn't need to replenish them so much. That is certainly my experience anyway.
Now, if I could just find some way to avoid using shampoo (Boots baby shampoo and not every day), I reckon I'd solve my itchy neck hairline as well. Ideas welcome.