Anything that frames the face is very important. Collars are the closest part of a garment to the face for most men. The scale of the collar is as important as the shape of it. A wider collar will balance a man's wider jaw, and a smaller collar will work best for a man with a longer face. A gentleman with a wide face who wears a smaller pointy collar is only accentuating the negative. Balance is the key to the most attractive look for each person. As for suiting, the full spread collar is almost never necessary unless you are a very broad gentleman and will be wearing a full Windsor knot tie. Jacket collars are supposed to be consistent with the breadth of the shoulders. Wider lapels can be best on a broader guy, and narrower collars on smaller builds. Peaked lapels are now considered completely acceptable. As long as the lapel is not in high contrast to the jacket, which will still look a little disco, and will need the right type of guy to pull it off (who must be under 30 or a rock star).