Gears of War has always impressed me with its interesting weapons. In the first one, there was the Torque Bow. In the second they added things like a mortar. In Gears of War 3, they've added ... well, a whole lot of new weapons. A Retro Lancer that has a bayonet instead of a chainsaw. Which lets you do a bayonet charge and skewer your enemies in the air. There's also, get this, a Cleaver. It's a giant sword that ... well, it seems fairly useless, at least on Hardcore difficulty ( enemies keep hitting me before I can even land a hit ), but the weapon is so awesome. If you run with it, you drag it along the ground. It has limited uses, so it's basically like the melee weapons from Halo. As badass, too. And powerful.
Edit: Ugh. There's a scene that is basically impossible to do properly without a co-op partner. I'm playing it alone now, and ... basically, you have to snipe two guys before they sound the alarm. With two players, it would've been a breeze. With just me ... well, I barely have time to reload after taking out one of them before the other one is gone, so ... yeah. I guess solo players just have to do it the hard way.
Edit2: To make up for it, there's something very primal and satisfying about bayonet charging a Theron with a cleaver who is charging you.