B-52s Would be better...
The B-52 has hard points inboard of the 3/4 and 5/6 engine pods that could easily handle a 750Kg, refrigerator-sized, death-dealing, 150Kw LASER. I've heard that it is about 20% efficient, meaning you'd need a 750Kw generator. Now the AF has just ordered a boatload of 800Kw generators, squeeze it down to fit inside a bomb bay, one for each weapon, pipe in JP-5 from the humongous fuel reserves (and It's in-flight refuelable so no worries about running out of gas), and voila! I present you with the LASER-Mega-Fortress. Probably have to re-designate it as the B-52L.
With two lasers on board, the crew would have the ability to tackle multiple targets, or be really nasty and slice/dice together. Put one over an inbound armada and you've got protection from SAMs, enemy aircraft, etc. Put a couple ground-based versions around a military outpost with clear fields of fire and you've got protection from mortars, rockets, cruise missiles, probably even dumb bombs (given enough time to burn through a casing).