I love terminators. A couple of codexes ago my Word Bearers were built around a core of terminators. Today the deamons provide a bit more of the cutty cutty, but the terminators are nearby to help.
Loyalists don’t miss out either. My first 40K army were Imperial Fists, and terminators were there right from the start.
Another classic bit of kit is an assault cannon. This dude is a dark angle model, I think, but he has come back into the bosom of a chapter without any dodgey secrets:
Lightning claws have their place, but thunder hammers really are all the rage now.
I find you can’t hold back with termies, especially those without any guns. Screw your courage to the sticking place and deep strike right next to something dangerous and get stuck in. This is particularly fun in apocalypse games and titans.
Of course, if you’re going to do that, then you might as well bring along the original stubborn bastard and his S10 AP1 hammer:
Lysander can be shot to death, like just about anyone else, but if you can get him into combat he is ace.
I still like the old school build: power fist and storm bolters. But whatever the build I rarely leave them out of a marine force.