I'm a big fan of the Eruptor as a primary, the Las-58 Talon laser pistol, and usually Incendiary grenades. I tend to favor the light Siege Ready armor, for faster reloads and extra ammo.
The Eruptor is just so strong against every faction. With it's Heavy Pen there aren't a lot of things it can't kill. It makes shortt work of tightly packed groups of chaff, it'll regularly one shot mediums like Devestators and 'Nid Warriors, and headshots will one shot squid overseers. It's also surprisingly effective against the Fleshmobs. Initially I'd been bringing the Machinegun support weapon to make up for close range targets, but the Talon has been more than suitable for that task.