I almost always go with heavy armor over light, and I'd rank them thus:
1. Dragonbone Armor: To me, this is the iconic Dragonborn armor. Forget the iron helmet and studded armor, this is the unique armor set that nobody else in Skyrim wears. Personally forged and enchanted by the Dragonborn himself, it grants him instant recognition in a crowd.
2. Ebony Armor: Ebony armor has a sleek and classic look, very 'knights in shining armor' with the bonus cool factor of being ominously black and having a face-concealing helmet that still looks decent.
3. Wolf Armor: This is another classic set, managing to look both badass and low-key at the same time. The wolf motif carries a special significance to werewolf characters, and it signifies membership in one of the most highly regarded factions in the game.
4. Heavy Dawnguard Armor: I've always liked the Dawnguard armor. It's not flashy, but it's different enough from the base-game armors that it stands out. It's clean and distinctive. The helmet is sort of goofy looking and doesn't really match the rest of the armor, but the shield design is one of the absolute best. A complete set of Dawnguard armor with shield and the Dawnbreaker sword, and you'll be a vampire's worst nightmare.