Dragonscale Armor set looks good on Argonians.
Heavy Falmer Armor looks also good on Argonians (maybe with the Orcish Helmet).
Cultist Armor/Clothes set (Dragonborn) looks very good on Argonians (specially the serpent on the shoulder) and combine it with the thieves guild hood.
Ancient Falmer Armor looks good on Kahjiit (specially if you have a snow white Kahjiit).
Oh and i often use Ulfric's Clothes or the Fur-Trimmed Cloak when i'm in a town or a settlement.
Here are the outfits I use. I tend toward the light armor and clothing, unenchanted so I can give them my own enchantments. A few pieces are acquired through console commands, but not many, and even those are enchantable. In the end, I go for what looks good and matches up. I'm not a fan of pre-enchanted objects, no matter how cool they look (with the cultist robes the exception here). Yes, Nightingale is slick, but my own enchantments far outweigh the look. Not sure if I'm a mage or a ranger or an assassin or whatever. Just want to turn heads in the Skyrim fashion show.
I use Archmage's Robes with Ulfric's bracers because they basically complement the hand area of your robes in such a way that without those bracers it doesn't feel right anymore. Like, it actually looks more badass with those bracers and better yet it doesn't affect Mage Armor despite having an armor rating.