MJOLNIR Mark V(full armor), actual ODST(full armor), & CQB(helmet & chest piece).
While I would also love these armors, I don't think I could justify paying money for them. Just on principle alone, because they should've been in the game from the get-go. (Granted, I might see why there are no ODST's in 4 considering there is no "orbit" to insert from on Requiem.)
But the mark V is THE classic armor, and shoud've been included.