I know it's not exactly a burger joint, but Ruby Tuesday's Triple Prime burger is my new favorite chain restaurant burger. Fuddrucker's makes a decent burger, but the real selling point for Fuddrucker's are the rolls they use. Man, they are so good. Red Robin makes some tasty burgers, but the rolls aren't nearly as good as Fuddrucker's. I've eaten at 2 Five Guys in the Baltimore Area and they were good, certainly better than your average burger joint, but not up there with the other 3.
So Ruby Tuesdays > Fuddruckers > Red Robin > Five Guys for me.