I'm not a huge fighter, but I enjoy some good looking highly valuable armor.
With 200m, and since you're looking for armour with cosmetic properties, I'd advise against bandos, and consider buying full Dragon, as well as ornamental kits for each part. This will give your dragon pieces a specific look:
(or) ornamental kits will give your dragon pieces a golden trim
(sp) ornamental kits will give your dragon pieces set extra spikes
Alternatively, you could use dragonbone kits to cover the armour in, well, dragonbone

which changes the look slightly, as well as turning the armour a purple colour.
Some prices for you;
Full Dragon (Full helmet, platebody, platelegs, kiteshield) : Under 12m
(or) kits (for the entire set) : Under 11m
(sp) kits (for the entire set) : 1.5m
Dragonbone kits (for the entire set + dragon boots + dragon gloves) : Around 2m
Alternatively, rather than a dragon shield, you could also consider an Arcane/Elysian/Divine spirit shield instead?
Or, instead of a Dragon full helm, you could purchase a green/blue h'ween mask, or even a santa hat
Personally, if I were you, I'd buy Dragon platebody, platelegs and kiteshield, along with the corresponding (or) ornamental kits and a santa hat

With Santa hats at 144 when I was flipping them yesterday, this "costume" would cost you, roughly, 165m
Hope this helps