Napalm worked in the Six Day War in Sinai but still has bad P.R. from Vietnam. Sure would be effective against these savages.
Fuel-air explosives would work well, too.
ISIS is not a form of Islam. ISIS is Islam in its purest evilest most concentrated form, no ifs, ands, or buts.
Since their weapon of choice for terror is FIRE, then let them REAP what they have sewn.