I am very late here (life has been crazy busy lately) but what a fascinating discussion, that you for starting it Staysfit!
I am another member of the Giraffe neck club, and my proportions are similar to Suz and UK Sue, with some differences. I have a very long neck ( and long arms, long upper body, long waist, long rise), and short legs on the other side. The shortness in my legs is in the thighs, the calves have relatively average length.
When it comes to considering necklines, I generally look better in higher ones. However, while I have long neck and small-to-medium bust, my shoulders are fairly square ( not very wide, but not narrow idea, they look sort of like clothes hanger) and I have longer hair, so I feel this allows me to get away with other more open necklines. I wear deeper V-s, wraps, halters, off-the shoulder necklines, sweethearts, strapless etc. I will admit that I am not a great judge on flattery of necklines, because I can say which are great (higher ones ) and which are horrible (super wide and open scoops) but most look medium flattering to me and if I like them I will wear them. At some point when I have time I will post a proportion lab type of post with various necklines for you to analyze which ones are good and which ones not so much.
Having very long waist and short legs, I do find what Suz says about skirts vs. pants and hiding the rise true. However, I wear jeans/pants 90% of the time so can not take advantage of that a lot. I think that tunics look fine on me, I actually wear tunic/shirtdress over skinnies silhouette fairly often.
I used to be very concerned about elongating my leg line ( wedges, never tucking into lower waist bottoms etc.), but in the past couple of years I have relaxed a lot and do a lot of JFE outfits in that respects - I wear lots of flats, semi-tucks and jeans rolled just above the ankle these days.