What is the best looking armor from each level rarity?
That’s a very large and very subjective question. I wont give a comprehensive answer of each rarity level, but…
My favorite armor set is Hermes. That’s the one I’m going for. I love the big visors of EVA, Interceptor, Orbital, etc, and that one looks even better than the rest.
Love the Cypher body but not the helmet. I like the angular chest piece that looks like it protects your chin and those wide shoulder pads.
All you need is Nightfall 
scout all the way.
I like the hunter armor
Anything in Halo reach. I miss my EOD