1. Minigun/Gatling laser: either is great, as both make stupendously short work of marked men, even irradiated MMs. They'll drop like flies, though obviously make sure you have a good supply of ammo as they chew through it at a good rate
2. Riot shotgun: this is the best anti-deathclaw gun, as long as you be sure to take the Shotgun Surgeon and Stay Back perks. Spam the trigger as they run at you, then close and execute when they get knocked down.
3. Anything else you find: there's tonnes of guns and ammo to be found, the SMMG is a good gun for general use and to conserve ammo for the others, and Red Glare is utterly demonic.
Any other setups?