The original design that caught my eye so long ago...
The original ODST design from Halo 2. Less armor than the Halo 3 ODSTs, but you can definitely tell the suits are related. Though, considering when Halo 3 ODST starts, that team REALLY should be in this armor, rather than the Halo 3 armor.
Unless one of two things happened... 1. Due to their mission, they were given the top of the line equipment, not yet seen in combat. Or 2. Halo 3 ODST retconned the old armor design out of continuity.
I'm thinking it's more option #2.
I started with just one... But after I found that the Battle Rifle covered most of his chest armor, I did a second... But having 2 just didn't look right, so I added a third.