Mine is Faraam from ds2. There's something about the ds2 vibe and aesthetic that I find so appealing. Also this armour just looks so good.
Runner up is fallen knight set from ds3 cos it looked really cool when embered and Lautrecs from ds1 cos bronz. Fluted set from demons is also very good.
I like the catarina set from ds1 because it feels very Berserk inspired, like so much of the game. Looks like Bazuso from the Golden Age arc.
I also love the Thorns set