It really comes down to preference. I think that if you want to have an enjoyable gaming experience and feel as though you've accomplished something without completely trivializing the game, then Arcane is the best of all of the Smithing perks. You actually get to upgrade those cool artifacts and make them much more useful than what they previously were, and this is important if you like the way they look and function.
It's not the "most powerful" approach. That would simply be accomplished by Smithing Daedric gear and then upgrading it with +%smithing items, then adding double enchantments on top. This however, totally trivializes everything about the combat on any difficulty and makes the "fun" factor take a nose dive.
If you really want to use Smithing, but don't want to break the game, then Arcane Blacksmith is your best bet.
Ok thanks, I don't have any interest in upgrading smithing since I only want to use artifacts...so I will invest the perk into arcane blacksmithing to improve the artifacts I find
Your Smithing skill matters though. You don't have to put anymore perks into the tree, but the actual skill level determins how high you can upgrade your gear. I don't know the exact requirements, but it's the difference between "Flawless", "Epic", "Legendary" and "Peerless". Getting 100 in Smithing is a must if you want to upgrade the Enchanted gear you find to their fullest without using +%Smithing gear. Adding +%Smithing gear only improves you that much more after skill level 100.