So what are your favorite armor sets and pieces from the Halo Universe? My favorite is definitely the Hayabusa armor from Halo 3.
Good ol’ Mark IV
Mark V Armor
Security Helmet (Halo 3 and Reach)
Gungnir Helmet
Mark VI Armor
Venator Helmet
Mark VI Armor
Recruit Helmet
ODST Armor
Mark v is always good, and you can’t go wrong with Mark VI, but I really like CIO for some reason I got it with my preorder of halo4 and I always seem to go back to it. I kind of like the vanguard too.
I’ve always found the Rogue helmet with Scout shoulders and Hayabusa chest to be the one I like the most. Just looks really cool to me.
Halo CE and 2: Hmm. I don’t know… 
Halo 3: Recon
Halo 3 ODST: Dutch with helmet
Halo Reach: Mark V
Halo 4: Too many to choose from!
Halo 5 Beta: Nightfall
CE and 2 doesn’t count
H3: Recon or Hayabusa
H3ODST: Rookie for no reason
HR: Scout or Basic
H4: Deadeye or Fotus
H5 Beta: Recon
Hard to say. Overall, I would have to say that the Scout armor has always been my favorite overall. I liked it in Halo 3, and loved the revised version in Halo 4 … except for the shoulder pieces. They reminded me of serving plates. Way too big for the armor.
But … in saying that … I’ve grown pretty fond of my Locus set up from Halo 4. (seen in my avatar) And I really liked my Gungnir set up from Reach as well.
So, I can’t pick just one. Those 3 would be in my top favorites.
I would have to say the Fotus armor set but for one that’s not exclusive it would be the Oceanic armor set
I love Chief’s and the Halo 3 - Reach ODST armor.
Aviator is one of my favorites.
I love the Scout armor in general from all of Halo. But my favorite armor build was from Halo 4 where I customized it to be:
Helmet: Scout APEX
Chest: Venator BYNT
Arms: Mark IV
Legs: Contoured
Shoulders: Iniltrator
From Reach also I really liked the Recon.