I've always liked this concept and I think it helps reflect the origin and purpose of different weaponry. I think Halo nailed it, but my personal favorite was Red Faction: Guerrilla, which had all the crudely drawn reticles for the marauder weapons, and the rigid angular style for the federal weapons. Dead Space also had such a fluid system which was so functional in addition to being a perfect and really an obvious match to the style of the tools and the theme of the game. Share your favorites, or maybe your least favorites