My Guardian wears trooper armor. I like the look.
My Sith Marauder has a nifty agent black trench coat looking thing, which just looks awesome with his two 'sabres.
My solution has been to put my Guardian in re-modded trooper armor.
Aside from the hood issue, my real problem with most Knight gear is that the Heavy Armor chest pieces tend to look painted on, not bulky and plated like the Trooper gear.