Voted for X-convict, but it uses design to its advantage. Ultimately, if this is going to be used for an RTS-game, this design is going to stand out the most (be memorable) and provide visual clues to the player (orange paint) about what it is. Simply, X-Convict's is the best suited for an RTS game.
Great work everyone! (shameless plug: I couldn't join in this challenge, but I posted up my submission in the non-voting topic... with some questions). I hope to join you in the next challenge with a submission that's turned in on time.
