Here are some of my favorite medium armor for the game:
T3 Human Cultural (though the underboob is WAY too "over the top" IMO):
Here are the currently available Medium Armor Sets:
Personally I think there needs to be more cool looking armor for leather wearers. I find only 3 or 4 to be pretty cool, IMO. I like to mix and match. Like right now my Engy is wearing the Whispers top with most of the Duelist's bottom pieces.