It is quite easy to swap out buttons on a quality jacket. If you have the type of jacket with cotter pins or split rings to hold them on it is a simple matter of finding where the slit is in the liner, reach in and pull the cotter pin and put a new button on.
It takes about 30 sec per button.

Any good button will work, it just depends on what you are looking for. Until the advent of the large retailers jackets were made in small shops and each had their own unique buttons. You could tell the maker from across the room by the buttons .

Visit your local sewing or fabric shop. Take a look at what is available. Remember though that in most cases simple equals elegant so if you have a choice find a good simple button.

I have used the leather knots, plain black, black fabric covered, and black military style, false and real antler, along with gold and silver. It's just style. What is yours?