I like all breeds of ducks and I think you can simply choose the ones who look the prettiest to you.
Of mine, my Silver Appleyards are extra big and very calm natured. They tend to be quiet and not get upset easily. They are excellent layers and very good table birds. Also, I think they are the most beautiful of all the ducks.
Welsh Harlequins are the best choice for a breed that lays lots of eggs. Most of the egg laying breeds are more high strung and WH are the most calm of the bunch. If what you want is a good source of eggs. Also, they are very beautiful.
I've got some Pekins right now who are in-your-face friendly. They climb all over me. I don't know if that is a breed characteristic, or it is just birds from this specific breeder. The Blue Swedish I got from him have the same wonderful temperament and that is not happening with Swedish from a hatchery. Those Swedish are high strung and freaked out about every little change.
Pekins have a reputation for being exceptionally noisy. Personally, I don't care for the solid white color, but many people like it. Pekins are large ducks and very fast growing. They are intended to be table ducks, but make good pets. Not the breed I'd choose if I wanted eggs.