One of the coolest powers I've tried lately and so far is Fire All Weapons from Power Armor.. It's almost like having an Active Defense on it's own cooldown timer with the power: Destroy Everything in Front of Me.
Even used as an opening attack with 1 stack of Concentration it can be a joy. My favorite thing when testing it was to lure everything I could survive and then start melting.
Have to have the build for it to truly enjoy it though. It's an energy hog and can have a lonnnnng recharge.