And I second Kill la Kill.
Let's see what else I have:
Akame ga Kill and Code Geass are two of my favorites (after Durarara). Mirai Nikki has great story (I think). Fate/Stay Night (Unlimited Blade Works), Fate/Zero, and Shin Sekai Yori (From the New World) are fairly good, with the first two having plenty of action. Monthly Girls' Nozaki-kun lacks the action, guns and mechs, but has plenty of fun. As soon as Space Patrol Luluco comes out, I'd recommend it. It, from the one episode I got to see early (), seems to have plenty of fun, some middle-school love, and maybe some action. It is going to be a series of shorts (about 5 minutes).