Make sure you give them some fire axes, seems to be one of the only melee weapons worth fearing.
I've just finished the Fiend's inventorys, Fire Axes, Rippers and Chainsaws. This is going to be a lot of fun with Increased wasteland spawns high setting.
"throw in some thrown weapons, so far i havent seen npcs use them. get it? throw in...thrown weap...sigh...never mind :tongue:"
Horrible, horrible pun, but a damned good idea

I reckon that'd fit the Great Khans pretty well.
So far I've got:
Powder Gangers with weakish melee weapons, but lots of dynamite.
2nd gen Super Mutants with heavy two handed melee weapons, with big guns support.
Night Kin don't get as many big guns because of the stealth.
Fiend's/Raider's have the cool damaging melee weapons.
Khan's are going to carry melee and thrown weapons.
Boomers could be Powder Gangers mk2, with frags and explosive weapon support.
NCR and BoS can stay pretty much as original, I think the firepower suits them.
That leaves Legion, Vipers and Jackals, that I'm not sure of. Particularly the Legion, since they're meant to be taking on the NCR's firepower...