The Duffle Coat
Otherwise known as the Toggle Coat because of the toggle buttons.
The first three jackets in this list had a specific purpose. The Chesterfield for dress, the Mackintosh for rain, the leather jacket for casual. The Duffle Coat is a great marriage between them. If you so desired, you can wear this with a suit if you dress it up with the scarf and hat/gloves. It also looks great with jeans. With that kind of versatility, this could be the first jacket you buy if you are starting over.
This coat should be of a heavier wool material as well, in the interest of warmth and longevity. The fit should be similar to that of the Chesterfield, longer than the waist but shorter than the knees, with the sleeves extending past the sleeves of the shirt. What sets this coat apart is the toggle buttons. There is a level of sophistication from the small detail, and a great way to elevate any look.
Flash it up- This jacket can look great as a grey or tan, opposite of the Chesterfield is ideal. (If your Chesterfield is a charcoal color, consider tan for this.) However, in an attempt to have a throwback to the British Royal Navy origins of this great piece, try a navy blue to put some color into your coats.